[yosys.git] / frontends / ast / ast.cc

/*
 *  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.
 *
 *  ---
 *
 *  This is the AST frontend library.
 *
 *  The AST frontend library is not a frontend on it's own but provides a
 *  generic abstract syntax tree (AST) abstraction for HDL code and can be
 *  used by HDL frontends. See "ast.h" for an overview of the API and the
 *  Verilog frontend for an usage example.
 *
 */

#include "kernel/log.h"
#include "libs/sha1/sha1.h"
#include "ast.h"

#include <sstream>
#include <stdarg.h>
#include <assert.h>

using namespace AST;
using namespace AST_INTERNAL;

// instanciate global variables (public API)
namespace AST {
        std::string current_filename;
        void (*set_line_num)(int) = NULL;
        int (*get_line_num)() = NULL;
}

// instanciate global variables (private API)
namespace AST_INTERNAL {
        bool flag_dump_ast1, flag_dump_ast2, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_autowire;
        AstNode *current_ast, *current_ast_mod;
        std::map<std::string, AstNode*> current_scope;
        RTLIL::SigSpec *genRTLIL_subst_from = NULL;
        RTLIL::SigSpec *genRTLIL_subst_to = NULL;
        RTLIL::SigSpec ignoreThisSignalsInInitial;
        AstNode *current_top_block, *current_block, *current_block_child;
        AstModule *current_module;
}

// convert node types to string
std::string AST::type2str(AstNodeType type)
{
        switch (type)
        {
#define X(_item) case _item: return #_item;
        X(AST_NONE)
        X(AST_DESIGN)
        X(AST_MODULE)
        X(AST_TASK)
        X(AST_FUNCTION)
        X(AST_WIRE)
        X(AST_MEMORY)
        X(AST_AUTOWIRE)
        X(AST_PARAMETER)
        X(AST_LOCALPARAM)
        X(AST_DEFPARAM)
        X(AST_PARASET)
        X(AST_ARGUMENT)
        X(AST_RANGE)
        X(AST_CONSTANT)
        X(AST_CELLTYPE)
        X(AST_IDENTIFIER)
        X(AST_PREFIX)
        X(AST_ASSERT)
        X(AST_FCALL)
        X(AST_TO_BITS)
        X(AST_TO_SIGNED)
        X(AST_TO_UNSIGNED)
        X(AST_CONCAT)
        X(AST_REPLICATE)
        X(AST_BIT_NOT)
        X(AST_BIT_AND)
        X(AST_BIT_OR)
        X(AST_BIT_XOR)
        X(AST_BIT_XNOR)
        X(AST_REDUCE_AND)
        X(AST_REDUCE_OR)
        X(AST_REDUCE_XOR)
        X(AST_REDUCE_XNOR)
        X(AST_REDUCE_BOOL)
        X(AST_SHIFT_LEFT)
        X(AST_SHIFT_RIGHT)
        X(AST_SHIFT_SLEFT)
        X(AST_SHIFT_SRIGHT)
        X(AST_LT)
        X(AST_LE)
        X(AST_EQ)
        X(AST_NE)
        X(AST_EQX)
        X(AST_NEX)
        X(AST_GE)
        X(AST_GT)
        X(AST_ADD)
        X(AST_SUB)
        X(AST_MUL)
        X(AST_DIV)
        X(AST_MOD)
        X(AST_POW)
        X(AST_POS)
        X(AST_NEG)
        X(AST_LOGIC_AND)
        X(AST_LOGIC_OR)
        X(AST_LOGIC_NOT)
        X(AST_TERNARY)
        X(AST_MEMRD)
        X(AST_MEMWR)
        X(AST_TCALL)
        X(AST_ASSIGN)
        X(AST_CELL)
        X(AST_PRIMITIVE)
        X(AST_ALWAYS)
        X(AST_INITIAL)
        X(AST_BLOCK)
        X(AST_ASSIGN_EQ)
        X(AST_ASSIGN_LE)
        X(AST_CASE)
        X(AST_COND)
        X(AST_DEFAULT)
        X(AST_FOR)
        X(AST_WHILE)
        X(AST_REPEAT)
        X(AST_GENVAR)
        X(AST_GENFOR)
        X(AST_GENIF)
        X(AST_GENCASE)
        X(AST_GENBLOCK)
        X(AST_POSEDGE)
        X(AST_NEGEDGE)
        X(AST_EDGE)
#undef X
        default:
                log_abort();
        }
}

// check if attribute exists and has non-zero value
bool AstNode::get_bool_attribute(RTLIL::IdString id)
{
        if (attributes.count(id) == 0)
                return false;

        AstNode *attr = attributes.at(id);
        if (attr->type != AST_CONSTANT)
                log_error("Attribute `%s' with non-constant value at %s:%d!\n",
                                id.c_str(), attr->filename.c_str(), attr->linenum);

        return attr->integer != 0;
}

// create new node (AstNode constructor)
// (the optional child arguments make it easier to create AST trees)
AstNode::AstNode(AstNodeType type, AstNode *child1, AstNode *child2)
{
        this->type = type;
        filename = current_filename;
        linenum = get_line_num();
        is_input = false;
        is_output = false;
        is_reg = false;
        is_signed = false;
        is_string = false;
        range_valid = false;
        port_id = 0;
        range_left = -1;
        range_right = 0;
        integer = 0;
        id2ast = NULL;
        basic_prep = false;

        if (child1)
                children.push_back(child1);
        if (child2)
                children.push_back(child2);
}

// create a (deep recursive) copy of a node
AstNode *AstNode::clone()
{
        AstNode *that = new AstNode;
        *that = *this;
        for (auto &it : that->children)
                it = it->clone();
        for (auto &it : that->attributes)
                it.second = it.second->clone();
        return that;
}

// create a (deep recursive) copy of a node use 'other' as target root node
void AstNode::cloneInto(AstNode *other)
{
        AstNode *tmp = clone();
        other->delete_children();
        *other = *tmp;
        tmp->children.clear();
        tmp->attributes.clear();
        delete tmp;
}

// delete all children in this node
void AstNode::delete_children()
{
        for (auto &it : children)
                delete it;
        children.clear();

        for (auto &it : attributes)
                delete it.second;
        attributes.clear();
}

// AstNode destructor
AstNode::~AstNode()
{
        delete_children();
}

// create a nice text representation of the node
// (traverse tree by recursion, use 'other' pointer for diffing two AST trees)
void AstNode::dumpAst(FILE *f, std::string indent)
{
        if (f == NULL) {
                for (auto f : log_files)
                        dumpAst(f, indent);
                return;
        }

        std::string type_name = type2str(type);
        fprintf(f, "%s%s <%s:%d>", indent.c_str(), type_name.c_str(), filename.c_str(), linenum);

        if (id2ast)
                fprintf(f, " [%p -> %p]", this, id2ast);
        else
                fprintf(f, " [%p]", this);

        if (!str.empty())
                fprintf(f, " str='%s'", str.c_str());
        if (!bits.empty()) {
                fprintf(f, " bits='");
                for (size_t i = bits.size(); i > 0; i--)
                        fprintf(f, "%c", bits[i-1] == RTLIL::S0 ? '0' :
                                        bits[i-1] == RTLIL::S1 ? '1' :
                                        bits[i-1] == RTLIL::Sx ? 'x' :
                                        bits[i-1] == RTLIL::Sz ? 'z' : '?');
                fprintf(f, "'(%zd)", bits.size());
        }
        if (is_input)
                fprintf(f, " input");
        if (is_output)
                fprintf(f, " output");
        if (is_reg)
                fprintf(f, " reg");
        if (is_signed)
                fprintf(f, " signed");
        if (port_id > 0)
                fprintf(f, " port=%d", port_id);
        if (range_valid || range_left != -1 || range_right != 0)
                fprintf(f, " range=[%d:%d]%s", range_left, range_right, range_valid ? "" : "!");
        if (integer != 0)
                fprintf(f, " int=%u", (int)integer);
        fprintf(f, "\n");

        for (auto &it : attributes) {
                fprintf(f, "%s  ATTR %s:\n", indent.c_str(), it.first.c_str());
                it.second->dumpAst(f, indent + "    ");
        }

        for (size_t i = 0; i < children.size(); i++)
                children[i]->dumpAst(f, indent + "  ");
}

// helper function for AstNode::dumpVlog()
static std::string id2vl(std::string txt)
{
        if (txt.size() > 1 && txt[0] == '\\')
                txt = txt.substr(1);
        for (size_t i = 0; i < txt.size(); i++) {
                if ('A' <= txt[i] && txt[i] <= 'Z') continue;
                if ('a' <= txt[i] && txt[i] <= 'z') continue;
                if ('0' <= txt[i] && txt[i] <= '9') continue;
                if (txt[i] == '_') continue;
                txt = "\\" + txt + " ";
                break;
        }
        return txt;
}

// dump AST node as verilog pseudo-code
void AstNode::dumpVlog(FILE *f, std::string indent)
{
        bool first = true;
        std::string txt;
        std::vector<AstNode*> rem_children1, rem_children2;

        if (f == NULL) {
                for (auto f : log_files)
                        dumpVlog(f, indent);
                return;
        }

        for (auto &it : attributes) {
                fprintf(f, "%s" "(* %s = ", indent.c_str(), id2vl(it.first).c_str());
                it.second->dumpVlog(f, "");
                fprintf(f, " *)%s", indent.empty() ? "" : "\n");
        }

        switch (type)
        {
        case AST_MODULE:
                fprintf(f, "%s" "module %s(", indent.c_str(), id2vl(str).c_str());
                for (auto child : children)
                        if (child->type == AST_WIRE && (child->is_input || child->is_output)) {
                                fprintf(f, "%s%s", first ? "" : ", ", id2vl(child->str).c_str());
                                first = false;
                        }
                fprintf(f, ");\n");

                for (auto child : children)
                        if (child->type == AST_PARAMETER || child->type == AST_LOCALPARAM || child->type == AST_DEFPARAM)
                                child->dumpVlog(f, indent + "  ");
                        else
                                rem_children1.push_back(child);

                for (auto child : rem_children1)
                        if (child->type == AST_WIRE || child->type == AST_AUTOWIRE || child->type == AST_MEMORY)
                                child->dumpVlog(f, indent + "  ");
                        else
                                rem_children2.push_back(child);
                rem_children1.clear();

                for (auto child : rem_children2)
                        if (child->type == AST_TASK || child->type == AST_FUNCTION)
                                child->dumpVlog(f, indent + "  ");
                        else
                                rem_children1.push_back(child);
                rem_children2.clear();

                for (auto child : rem_children1)
                        child->dumpVlog(f, indent + "  ");
                rem_children1.clear();

                fprintf(f, "%s" "endmodule\n", indent.c_str());
                break;

        case AST_WIRE:
                if (is_input && is_output)
                        fprintf(f, "%s" "inout", indent.c_str());
                else if (is_input)
                        fprintf(f, "%s" "input", indent.c_str());
                else if (is_output)
                        fprintf(f, "%s" "output", indent.c_str());
                else if (!is_reg)
                        fprintf(f, "%s" "wire", indent.c_str());
                if (is_reg)
                        fprintf(f, "%s" "reg", (is_input || is_output) ? " " : indent.c_str());
                if (is_signed)
                        fprintf(f, " signed");
                for (auto child : children) {
                        fprintf(f, " ");
                        child->dumpVlog(f, "");
                }
                fprintf(f, " %s", id2vl(str).c_str());
                fprintf(f, ";\n");
                break;

        case AST_MEMORY:
                fprintf(f, "%s" "memory", indent.c_str());
                if (is_signed)
                        fprintf(f, " signed");
                for (auto child : children) {
                        fprintf(f, " ");
                        child->dumpVlog(f, "");
                        if (first)
                                fprintf(f, " %s", id2vl(str).c_str());
                        first = false;
                }
                fprintf(f, ";\n");
                break;

        case AST_RANGE:
                if (range_valid)
                        fprintf(f, "[%d:%d]", range_left, range_right);
                else {
                        for (auto child : children) {
                                fprintf(f, "%c", first ? '[' : ':');
                                child->dumpVlog(f, "");
                                first = false;
                        }
                        fprintf(f, "]");
                }
                break;

        case AST_ALWAYS:
                fprintf(f, "%s" "always @(", indent.c_str());
                for (auto child : children) {
                        if (child->type != AST_POSEDGE && child->type != AST_NEGEDGE && child->type != AST_EDGE)
                                continue;
                        if (!first)
                                fprintf(f, ", ");
                        child->dumpVlog(f, "");
                        first = false;
                }
                fprintf(f, ")\n");
                for (auto child : children) {
                        if (child->type != AST_POSEDGE && child->type != AST_NEGEDGE && child->type != AST_EDGE)
                                child->dumpVlog(f, indent + "  ");
                }
                break;

        case AST_INITIAL:
                fprintf(f, "%s" "initial\n", indent.c_str());
                for (auto child : children) {
                        if (child->type != AST_POSEDGE && child->type != AST_NEGEDGE && child->type != AST_EDGE)
                                child->dumpVlog(f, indent + "  ");
                }
                break;

        case AST_POSEDGE:
        case AST_NEGEDGE:
        case AST_EDGE:
                if (type == AST_POSEDGE)
                        fprintf(f, "posedge ");
                if (type == AST_NEGEDGE)
                        fprintf(f, "negedge ");
                for (auto child : children)
                        child->dumpVlog(f, "");
                break;

        case AST_IDENTIFIER:
                fprintf(f, "%s", id2vl(str).c_str());
                for (auto child : children)
                        child->dumpVlog(f, "");
                break;

        case AST_CONSTANT:
                if (!str.empty())
                        fprintf(f, "\"%s\"", str.c_str());
                else if (bits.size() == 32)
                        fprintf(f, "%d", RTLIL::Const(bits).as_int());
                else
                        fprintf(f, "%zd'b %s", bits.size(), RTLIL::Const(bits).as_string().c_str());
                break;

        case AST_BLOCK:
                if (children.size() == 1) {
                        children[0]->dumpVlog(f, indent);
                } else {
                        fprintf(f, "%s" "begin\n", indent.c_str());
                        for (auto child : children)
                                child->dumpVlog(f, indent + "  ");
                        fprintf(f, "%s" "end\n", indent.c_str());
                }
                break;

        case AST_CASE:
                fprintf(f, "%s" "case (", indent.c_str());
                children[0]->dumpVlog(f, "");
                fprintf(f, ")\n");
                for (size_t i = 1; i < children.size(); i++) {
                        AstNode *child = children[i];
                        child->dumpVlog(f, indent + "  ");
                }
                fprintf(f, "%s" "endcase\n", indent.c_str());
                break;

        case AST_COND:
                for (auto child : children) {
                        if (child->type == AST_BLOCK) {
                                fprintf(f, ":\n");
                                child->dumpVlog(f, indent + "  ");
                                first = true;
                        } else {
                                fprintf(f, "%s", first ? indent.c_str() : ", ");
                                if (child->type == AST_DEFAULT)
                                        fprintf(f, "default");
                                else
                                        child->dumpVlog(f, "");
                                first = false;
                        }
                }
                break;

        case AST_ASSIGN_EQ:
        case AST_ASSIGN_LE:
                fprintf(f, "%s", indent.c_str());
                children[0]->dumpVlog(f, "");
                fprintf(f, " %s ", type == AST_ASSIGN_EQ ? "=" : "<=");
                children[1]->dumpVlog(f, "");
                fprintf(f, ";\n");
                break;

        case AST_CONCAT:
                fprintf(f, "{");
                for (auto child : children) {
                        if (!first)
                                fprintf(f, ", ");
                        child->dumpVlog(f, "");
                        first = false;
                }
                fprintf(f, "}");
                break;

        case AST_REPLICATE:
                fprintf(f, "{");
                children[0]->dumpVlog(f, "");
                fprintf(f, "{");
                children[1]->dumpVlog(f, "");
                fprintf(f, "}}");
                break;
        
        if (0) { case AST_BIT_NOT:     txt = "~";  }
        if (0) { case AST_REDUCE_AND:  txt = "&";  }
        if (0) { case AST_REDUCE_OR:   txt = "|";  }
        if (0) { case AST_REDUCE_XOR:  txt = "^";  }
        if (0) { case AST_REDUCE_XNOR: txt = "~^"; }
        if (0) { case AST_REDUCE_BOOL: txt = "|";  }
        if (0) { case AST_POS:         txt = "+";  }
        if (0) { case AST_NEG:         txt = "-";  }
        if (0) { case AST_LOGIC_NOT:   txt = "!";  }
                fprintf(f, "%s(", txt.c_str());
                children[0]->dumpVlog(f, "");
                fprintf(f, ")");
                break;

        if (0) { case AST_BIT_AND:      txt = "&";   }
        if (0) { case AST_BIT_OR:       txt = "|";   }
        if (0) { case AST_BIT_XOR:      txt = "^";   }
        if (0) { case AST_BIT_XNOR:     txt = "~^";  }
        if (0) { case AST_SHIFT_LEFT:   txt = "<<";  }
        if (0) { case AST_SHIFT_RIGHT:  txt = ">>";  }
        if (0) { case AST_SHIFT_SLEFT:  txt = "<<<"; }
        if (0) { case AST_SHIFT_SRIGHT: txt = ">>>"; }
        if (0) { case AST_LT:           txt = "<";   }
        if (0) { case AST_LE:           txt = "<=";  }
        if (0) { case AST_EQ:           txt = "==";  }
        if (0) { case AST_NE:           txt = "!=";  }
        if (0) { case AST_EQX:          txt = "===";  }
        if (0) { case AST_NEX:          txt = "!==";  }
        if (0) { case AST_GE:           txt = ">=";  }
        if (0) { case AST_GT:           txt = ">";   }
        if (0) { case AST_ADD:          txt = "+";   }
        if (0) { case AST_SUB:          txt = "-";   }
        if (0) { case AST_MUL:          txt = "*";   }
        if (0) { case AST_DIV:          txt = "/";   }
        if (0) { case AST_MOD:          txt = "%";   }
        if (0) { case AST_POW:          txt = "**";  }
        if (0) { case AST_LOGIC_AND:    txt = "&&";  }
        if (0) { case AST_LOGIC_OR:     txt = "||";  }
                fprintf(f, "(");
                children[0]->dumpVlog(f, "");
                fprintf(f, ")%s(", txt.c_str());
                children[1]->dumpVlog(f, "");
                fprintf(f, ")");
                break;

        case AST_TERNARY:
                fprintf(f, "(");
                children[0]->dumpVlog(f, "");
                fprintf(f, ") ? (");
                children[1]->dumpVlog(f, "");
                fprintf(f, ") : (");
                children[2]->dumpVlog(f, "");
                fprintf(f, ")");
                break;

        default:
                std::string type_name = type2str(type);
                fprintf(f, "%s" "/** %s **/%s", indent.c_str(), type_name.c_str(), indent.empty() ? "" : "\n");
                // dumpAst(f, indent, NULL);
        }
}

// check if two AST nodes are identical
bool AstNode::operator==(const AstNode &other) const
{
        if (type != other.type)
                return false;
        if (children.size() != other.children.size())
                return false;
        if (str != other.str)
                return false;
        if (bits != other.bits)
                return false;
        if (is_input != other.is_input)
                return false;
        if (is_output != other.is_output)
                return false;
        if (is_reg != other.is_reg)
                return false;
        if (is_signed != other.is_signed)
                return false;
        if (is_string != other.is_string)
                return false;
        if (range_valid != other.range_valid)
                return false;
        if (port_id != other.port_id)
                return false;
        if (range_left != other.range_left)
                return false;
        if (range_right != other.range_right)
                return false;
        if (integer != other.integer)
                return false;
        for (size_t i = 0; i < children.size(); i++)
                if (*children[i] != *other.children[i])
                        return false;
        return true;
}

// check if two AST nodes are not identical
bool AstNode::operator!=(const AstNode &other) const
{
        return !(*this == other);
}

// check if this AST contains the given node
bool AstNode::contains(const AstNode *other) const
{
        if (this == other)
                return true;
        for (auto child : children)
                if (child->contains(other))
                        return true;
        return false;
}

// create an AST node for a constant (using a 32 bit int as value)
AstNode *AstNode::mkconst_int(uint32_t v, bool is_signed, int width)
{
        AstNode *node = new AstNode(AST_CONSTANT);
        node->integer = v;
        node->is_signed = is_signed;
        for (int i = 0; i < width; i++) {
                node->bits.push_back((v & 1) ? RTLIL::S1 : RTLIL::S0);
                v = v >> 1;
        }
        node->range_valid = true;
        node->range_left = width-1;
        node->range_right = 0;
        return node;
}

// create an AST node for a constant (using a bit vector as value)
AstNode *AstNode::mkconst_bits(const std::vector<RTLIL::State> &v, bool is_signed)
{
        AstNode *node = new AstNode(AST_CONSTANT);
        node->is_signed = is_signed;
        node->bits = v;
        for (size_t i = 0; i < 32; i++) {
                if (i < node->bits.size())
                        node->integer |= (node->bits[i] == RTLIL::S1) << i;
                else if (is_signed)
                        node->integer |= (node->bits.back() == RTLIL::S1) << i;
        }
        node->range_valid = true;
        node->range_left = node->bits.size()-1;
        node->range_right = 0;
        return node;
}

// create an AST node for a constant (using a string in bit vector form as value)
AstNode *AstNode::mkconst_str(const std::vector<RTLIL::State> &v)
{
        AstNode *node = mkconst_str(RTLIL::Const(v).decode_string());
        log_assert(node->bits == v);
        return node;
}

// create an AST node for a constant (using a string as value)
AstNode *AstNode::mkconst_str(const std::string &str)
{
        std::vector<RTLIL::State> data;
        data.reserve(str.size() * 8);
        for (size_t i = 0; i < str.size(); i++) {
                unsigned char ch = str[str.size() - i - 1];
                for (int j = 0; j < 8; j++) {
                        data.push_back((ch & 1) ? RTLIL::S1 : RTLIL::S0);
                        ch = ch >> 1;
                }
        }
        AstNode *node = AstNode::mkconst_bits(data, false);
        node->is_string = true;
        node->str = str;
        return node;
}

RTLIL::Const AstNode::bitsAsConst(int width, bool is_signed)
{
        std::vector<RTLIL::State> bits = this->bits;
        if (width >= 0 && width < int(bits.size()))
                bits.resize(width);
        if (width >= 0 && width > int(bits.size())) {
                RTLIL::State extbit = RTLIL::State::S0;
                if (is_signed && !bits.empty())
                        extbit = bits.back();
                while (width > int(bits.size()))
                        bits.push_back(extbit);
        }
        return RTLIL::Const(bits);
}

RTLIL::Const AstNode::bitsAsConst(int width)
{
        return bitsAsConst(width, is_signed);
}

RTLIL::Const AstNode::asAttrConst()
{
        log_assert(type == AST_CONSTANT);

        RTLIL::Const val;
        val.bits = bits;

        if (is_string) {
                val.flags |= RTLIL::CONST_FLAG_STRING;
                log_assert(val.decode_string() == str);
        }

        return val;
}

RTLIL::Const AstNode::asParaConst()
{
        RTLIL::Const val = asAttrConst();
        if (is_signed)
                val.flags |= RTLIL::CONST_FLAG_SIGNED;
        return val;
}

bool AstNode::asBool()
{
        log_assert(type == AST_CONSTANT);
        for (auto &bit : bits)
                if (bit == RTLIL::State::S1)
                        return true;
        return false;
}

// create a new AstModule from an AST_MODULE AST node
static AstModule* process_module(AstNode *ast, bool defer)
{
        assert(ast->type == AST_MODULE);

        if (defer)
                log("Storing AST representation for module `%s'.\n", ast->str.c_str());
        else
                log("Generating RTLIL representation for module `%s'.\n", ast->str.c_str());

        current_module = new AstModule;
        current_module->ast = NULL;
        current_module->name = ast->str;
        current_module->attributes["\\src"] = stringf("%s:%d", ast->filename.c_str(), ast->linenum);

        current_ast_mod = ast;
        AstNode *ast_before_simplify = ast->clone();

        if (flag_dump_ast1) {
                log("Dumping verilog AST before simplification:\n");
                ast->dumpAst(NULL, "    ");
                log("--- END OF AST DUMP ---\n");
        }

        if (!defer)
        {
                while (ast->simplify(!flag_noopt, false, false, 0, -1, false, false)) { }

                if (flag_dump_ast2) {
                        log("Dumping verilog AST after simplification:\n");
                        ast->dumpAst(NULL, "    ");
                        log("--- END OF AST DUMP ---\n");
                }

                if (flag_dump_vlog) {
                        log("Dumping verilog AST (as requested by dump_vlog option):\n");
                        ast->dumpVlog(NULL, "    ");
                        log("--- END OF AST DUMP ---\n");
                }

                if (flag_lib) {
                        std::vector<AstNode*> new_children;
                        for (auto child : ast->children) {
                                if (child->type == AST_WIRE && (child->is_input || child->is_output))
                                        new_children.push_back(child);
                                else
                                        delete child;
                        }
                        ast->children.swap(new_children);
                        ast->attributes["\\blackbox"] = AstNode::mkconst_int(1, false);
                }

                ignoreThisSignalsInInitial = RTLIL::SigSpec();

                for (auto &attr : ast->attributes) {
                        if (attr.second->type != AST_CONSTANT)
                                log_error("Attribute `%s' with non-constant value at %s:%d!\n",
                                                attr.first.c_str(), ast->filename.c_str(), ast->linenum);
                        current_module->attributes[attr.first] = attr.second->asAttrConst();
                }
                for (size_t i = 0; i < ast->children.size(); i++) {
                        AstNode *node = ast->children[i];
                        if (node->type == AST_WIRE || node->type == AST_MEMORY)
                                node->genRTLIL();
                }
                for (size_t i = 0; i < ast->children.size(); i++) {
                        AstNode *node = ast->children[i];
                        if (node->type != AST_WIRE && node->type != AST_MEMORY && node->type != AST_INITIAL)
                                node->genRTLIL();
                }

                ignoreThisSignalsInInitial.sort_and_unify();

                for (size_t i = 0; i < ast->children.size(); i++) {
                        AstNode *node = ast->children[i];
                        if (node->type == AST_INITIAL)
                                node->genRTLIL();
                }

                ignoreThisSignalsInInitial = RTLIL::SigSpec();
        }

        current_module->ast = ast_before_simplify;
        current_module->nolatches = flag_nolatches;
        current_module->nomem2reg = flag_nomem2reg;
        current_module->mem2reg = flag_mem2reg;
        current_module->lib = flag_lib;
        current_module->noopt = flag_noopt;
        current_module->icells = flag_icells;
        current_module->autowire = flag_autowire;
        return current_module;
}

// create AstModule instances for all modules in the AST tree and add them to 'design'
void AST::process(RTLIL::Design *design, AstNode *ast, bool dump_ast1, bool dump_ast2, bool dump_vlog, bool nolatches, bool nomem2reg, bool mem2reg, bool lib, bool noopt, bool icells, bool ignore_redef, bool defer, bool autowire)
{
        current_ast = ast;
        flag_dump_ast1 = dump_ast1;
        flag_dump_ast2 = dump_ast2;
        flag_dump_vlog = dump_vlog;
        flag_nolatches = nolatches;
        flag_nomem2reg = nomem2reg;
        flag_mem2reg = mem2reg;
        flag_lib = lib;
        flag_noopt = noopt;
        flag_icells = icells;
        flag_autowire = autowire;

        assert(current_ast->type == AST_DESIGN);
        for (auto it = current_ast->children.begin(); it != current_ast->children.end(); it++) {
                if (flag_icells && (*it)->str.substr(0, 2) == "\\$")
                        (*it)->str = (*it)->str.substr(1);
                if (defer)
                        (*it)->str = "$abstract" + (*it)->str;
                if (design->modules.count((*it)->str)) {
                        if (!ignore_redef)
                                log_error("Re-definition of module `%s' at %s:%d!\n",
                                                (*it)->str.c_str(), (*it)->filename.c_str(), (*it)->linenum);
                        log_error("Ignoring re-definition of module `%s' at %s:%d!\n",
                                        (*it)->str.c_str(), (*it)->filename.c_str(), (*it)->linenum);
                        continue;
                }
                design->modules[(*it)->str] =  process_module(*it, defer);
        }
}

// AstModule destructor
AstModule::~AstModule()
{
        if (ast != NULL)
                delete ast;
}

// create a new parametric module (when needed) and return the name of the generated module
RTLIL::IdString AstModule::derive(RTLIL::Design *design, std::map<RTLIL::IdString, RTLIL::Const> parameters)
{
        std::string stripped_name = name;

        if (stripped_name.substr(0, 9) == "$abstract")
                stripped_name = stripped_name.substr(9);

        log_header("Executing AST frontend in derive mode using pre-parsed AST for module `%s'.\n", stripped_name.c_str());

        current_ast = NULL;
        flag_dump_ast1 = false;
        flag_dump_ast2 = false;
        flag_dump_vlog = false;
        flag_nolatches = nolatches;
        flag_nomem2reg = nomem2reg;
        flag_mem2reg = mem2reg;
        flag_lib = lib;
        flag_noopt = noopt;
        flag_icells = icells;
        flag_autowire = autowire;
        use_internal_line_num();

        std::string para_info;
        std::vector<unsigned char> hash_data;
        hash_data.insert(hash_data.end(), stripped_name.begin(), stripped_name.end());
        hash_data.push_back(0);

        AstNode *new_ast = ast->clone();

        int para_counter = 0;
        int orig_parameters_n = parameters.size();
        for (auto it = new_ast->children.begin(); it != new_ast->children.end(); it++) {
                AstNode *child = *it;
                if (child->type != AST_PARAMETER)
                        continue;
                para_counter++;
                std::string para_id = child->str;
                if (parameters.count(para_id) > 0) {
                        log("Parameter %s = %s\n", child->str.c_str(), log_signal(RTLIL::SigSpec(parameters[child->str])));
        rewrite_parameter:
                        para_info += stringf("%s=%s", child->str.c_str(), log_signal(RTLIL::SigSpec(parameters[para_id])));
                        delete child->children.at(0);
                        child->children[0] = AstNode::mkconst_bits(parameters[para_id].bits, (parameters[para_id].flags & RTLIL::CONST_FLAG_SIGNED) != 0);
                        hash_data.insert(hash_data.end(), child->str.begin(), child->str.end());
                        hash_data.push_back(0);
                        hash_data.insert(hash_data.end(), parameters[para_id].bits.begin(), parameters[para_id].bits.end());
                        hash_data.push_back(0xff);
                        parameters.erase(para_id);
                        continue;
                }
                para_id = stringf("$%d", para_counter);
                if (parameters.count(para_id) > 0) {
                        log("Parameter %d (%s) = %s\n", para_counter, child->str.c_str(), log_signal(RTLIL::SigSpec(parameters[para_id])));
                        goto rewrite_parameter;
                }
        }
        if (parameters.size() > 0)
                log_error("Requested parameter `%s' does not exist in module `%s'!\n", parameters.begin()->first.c_str(), stripped_name.c_str());

        std::string modname;

        if (orig_parameters_n == 0)
        {
                modname = stripped_name;
        }
        else
        if (para_info.size() > 60)
        {
                unsigned char hash[20];
                unsigned char *hash_data2 = new unsigned char[hash_data.size()];
                for (size_t i = 0; i < hash_data.size(); i++)
                        hash_data2[i] = hash_data[i];
                sha1::calc(hash_data2, hash_data.size(), hash);
                delete[] hash_data2;

                char hexstring[41];
                sha1::toHexString(hash, hexstring);

                modname = "$paramod$" + std::string(hexstring) + stripped_name;
        }
        else
        {
                modname = "$paramod" + stripped_name + para_info;
        }

        if (design->modules.count(modname) == 0) {
                new_ast->str = modname;
                design->modules[modname] = process_module(new_ast, false);
                design->modules[modname]->check();
        } else {
                log("Found cached RTLIL representation for module `%s'.\n", modname.c_str());
        }

        delete new_ast;
        return modname;
}

RTLIL::Module *AstModule::clone() const
{
        AstModule *new_mod = new AstModule;
        cloneInto(new_mod);

        new_mod->ast = ast->clone();
        new_mod->nolatches = nolatches;
        new_mod->nomem2reg = nomem2reg;
        new_mod->mem2reg = mem2reg;
        new_mod->lib = lib;
        new_mod->noopt = noopt;
        new_mod->icells = icells;
        new_mod->autowire = autowire;

        return new_mod;
}

// internal dummy line number callbacks
namespace {
        int internal_line_num;
        void internal_set_line_num(int n) {
                internal_line_num = n;
        }
        int internal_get_line_num() {
                return internal_line_num;
        }
}

// use internal dummy line number callbacks
void AST::use_internal_line_num()
{
        set_line_num = &internal_set_line_num;
        get_line_num = &internal_get_line_num;
}