// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Clock Domain Crossing Lint
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2021 by Wilson Snyder. This program is free software; you
// can redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//*************************************************************************
// V3Cdc's Transformations:
//
// Create V3Graph-ish graph
// Find all negedge reset flops
// Trace back to previous flop
//
//*************************************************************************

#include "config_build.h"
#include "verilatedos.h"

#include "V3Global.h"
#include "V3Cdc.h"
#include "V3Ast.h"
#include "V3Graph.h"
#include "V3Const.h"
#include "V3EmitV.h"
#include "V3File.h"

#include <algorithm>
#include <deque>
#include <iomanip>
#include <memory>

constexpr int CDC_WEIGHT_ASYNC = 0x1000;  // Weight for edges that feed async logic

//######################################################################

class CdcBaseVisitor VL_NOT_FINAL : public AstNVisitor {
public:
    VL_DEBUG_FUNC;  // Declare debug()
};

//######################################################################
// Graph support classes

class CdcEitherVertex VL_NOT_FINAL : public V3GraphVertex {
    AstScope* m_scopep;
    AstNode* m_nodep;
    AstSenTree* m_srcDomainp = nullptr;
    AstSenTree* m_dstDomainp = nullptr;
    bool m_srcDomainSet : 1;
    bool m_dstDomainSet : 1;
    bool m_asyncPath : 1;

public:
    CdcEitherVertex(V3Graph* graphp, AstScope* scopep, AstNode* nodep)
        : V3GraphVertex{graphp}
        , m_scopep{scopep}
        , m_nodep{nodep}
        , m_srcDomainSet{false}
        , m_dstDomainSet{false}
        , m_asyncPath{false} {}
    virtual ~CdcEitherVertex() override = default;
    // ACCESSORS
    virtual FileLine* fileline() const override { return nodep()->fileline(); }
    AstScope* scopep() const { return m_scopep; }
    AstNode* nodep() const { return m_nodep; }
    AstSenTree* srcDomainp() const { return m_srcDomainp; }
    void srcDomainp(AstSenTree* nodep) { m_srcDomainp = nodep; }
    bool srcDomainSet() const { return m_srcDomainSet; }
    void srcDomainSet(bool flag) { m_srcDomainSet = flag; }
    AstSenTree* dstDomainp() const { return m_dstDomainp; }
    void dstDomainp(AstSenTree* nodep) { m_dstDomainp = nodep; }
    bool dstDomainSet() const { return m_dstDomainSet; }
    void dstDomainSet(bool flag) { m_dstDomainSet = flag; }
    bool asyncPath() const { return m_asyncPath; }
    void asyncPath(bool flag) { m_asyncPath = flag; }
};

class CdcVarVertex final : public CdcEitherVertex {
    AstVarScope* m_varScp;
    int m_cntAsyncRst = 0;
    bool m_fromFlop = false;

public:
    CdcVarVertex(V3Graph* graphp, AstScope* scopep, AstVarScope* varScp)
        : CdcEitherVertex{graphp, scopep, varScp}
        , m_varScp{varScp} {}
    virtual ~CdcVarVertex() override = default;
    // ACCESSORS
    AstVarScope* varScp() const { return m_varScp; }
    virtual string name() const override { return (cvtToHex(m_varScp) + " " + varScp()->name()); }
    virtual string dotColor() const override {
        return fromFlop() ? "green" : cntAsyncRst() ? "red" : "blue";
    }
    int cntAsyncRst() const { return m_cntAsyncRst; }
    void cntAsyncRst(int flag) { m_cntAsyncRst = flag; }
    bool fromFlop() const { return m_fromFlop; }
    void fromFlop(bool flag) { m_fromFlop = flag; }
};

class CdcLogicVertex final : public CdcEitherVertex {
    bool m_hazard : 1;
    bool m_isFlop : 1;

public:
    CdcLogicVertex(V3Graph* graphp, AstScope* scopep, AstNode* nodep, AstSenTree* sensenodep)
        : CdcEitherVertex{graphp, scopep, nodep}
        , m_hazard{false}
        , m_isFlop{false} {
        srcDomainp(sensenodep);
        dstDomainp(sensenodep);
    }
    virtual ~CdcLogicVertex() override = default;
    // ACCESSORS
    virtual string name() const override {
        return (cvtToHex(nodep()) + "@" + scopep()->prettyName());
    }
    virtual string dotColor() const override { return hazard() ? "black" : "yellow"; }
    bool hazard() const { return m_hazard; }
    void setHazard(AstNode* nodep) {
        m_hazard = true;
        nodep->user3(true);
    }
    void clearHazard() { m_hazard = false; }
    bool isFlop() const { return m_isFlop; }
    void isFlop(bool flag) { m_isFlop = flag; }
};

//######################################################################

class CdcDumpVisitor final : public CdcBaseVisitor {
private:
    // NODE STATE
    // Entire netlist:
    // {statement}Node::user3   -> bool, indicating not hazard
    std::ofstream* m_ofp;  // Output file
    string m_prefix;

    virtual void visit(AstNode* nodep) override {
        *m_ofp << m_prefix;
        if (nodep->user3()) {
            *m_ofp << " %%";
        } else {
            *m_ofp << "  ";
        }
        *m_ofp << nodep->prettyTypeName() << "\n";
        string lastPrefix = m_prefix;
        m_prefix = lastPrefix + "1:";
        iterateAndNextNull(nodep->op1p());
        m_prefix = lastPrefix + "2:";
        iterateAndNextNull(nodep->op2p());
        m_prefix = lastPrefix + "3:";
        iterateAndNextNull(nodep->op3p());
        m_prefix = lastPrefix + "4:";
        iterateAndNextNull(nodep->op4p());
        m_prefix = lastPrefix;
    }

public:
    // CONSTRUCTORS
    CdcDumpVisitor(AstNode* nodep, std::ofstream* ofp, const string& prefix)
        : m_ofp{ofp}
        , m_prefix{prefix} {
        iterate(nodep);
    }
    virtual ~CdcDumpVisitor() override = default;
};

//######################################################################

class CdcWidthVisitor final : public CdcBaseVisitor {
private:
    int m_maxLineno = 0;
    size_t m_maxFilenameLen = 0;

    virtual void visit(AstNode* nodep) override {
        iterateChildren(nodep);
        // Keeping line+filename lengths separate is much faster than calling ascii().length()
        if (nodep->fileline()->lineno() >= m_maxLineno) {
            m_maxLineno = nodep->fileline()->lineno() + 1;
        }
        if (nodep->fileline()->filename().length() >= m_maxFilenameLen) {
            m_maxFilenameLen = nodep->fileline()->filename().length() + 1;
        }
    }

public:
    // CONSTRUCTORS
    explicit CdcWidthVisitor(AstNode* nodep) { iterate(nodep); }
    virtual ~CdcWidthVisitor() override = default;
    // ACCESSORS
    int maxWidth() const {
        size_t width = 1;
        width += m_maxFilenameLen;
        width += 1;  // The :
        width += cvtToStr(m_maxLineno).length();
        width += 1;  // Final :
        return static_cast<int>(width);
    }
};

//######################################################################
// Cdc class functions

class CdcVisitor final : public CdcBaseVisitor {
private:
    // NODE STATE
    // Entire netlist:
    // AstVarScope::user1p      -> CdcVarVertex* for usage var, 0=not set yet
    // AstVarScope::user2       -> bool  Used in sensitivity list
    // {statement}Node::user1p  -> CdcLogicVertex* for this statement
    // AstNode::user3           -> bool  True indicates to print %% (via V3EmitV)
    AstUser1InUse m_inuser1;
    AstUser2InUse m_inuser2;
    AstUser3InUse m_inuser3;

    // STATE
    V3Graph m_graph;  // Scoreboard of var usages/dependencies
    CdcLogicVertex* m_logicVertexp = nullptr;  // Current statement being tracked, nullptr=ignored
    AstScope* m_scopep = nullptr;  // Current scope being processed
    AstNodeModule* m_modp = nullptr;  // Current module
    AstSenTree* m_domainp = nullptr;  // Current sentree
    bool m_inDly = false;  // In delayed assign
    int m_inSenItem = 0;  // Number of senitems
    string m_ofFilename;  // Output filename
    std::ofstream* m_ofp;  // Output file
    uint32_t m_userGeneration = 0;  // Generation count to avoid slow userClearVertices
    int m_filelineWidth = 0;  // Characters in longest fileline

    // METHODS
    void iterateNewStmt(AstNode* nodep) {
        if (m_scopep) {
            UINFO(4, "   STMT " << nodep << endl);
            m_logicVertexp = new CdcLogicVertex(&m_graph, m_scopep, nodep, m_domainp);
            if (m_domainp && m_domainp->hasClocked()) {  // To/from a flop
                m_logicVertexp->isFlop(true);
                m_logicVertexp->srcDomainp(m_domainp);
                m_logicVertexp->srcDomainSet(true);
                m_logicVertexp->dstDomainp(m_domainp);
                m_logicVertexp->dstDomainSet(true);
            }
            iterateChildren(nodep);
            m_logicVertexp = nullptr;

            if (false && debug() >= 9) {
                UINFO(9, "Trace Logic:\n");
                nodep->dumpTree(cout, "-log1: ");
            }
        }
    }

    CdcVarVertex* makeVarVertex(AstVarScope* varscp) {
        CdcVarVertex* vertexp = reinterpret_cast<CdcVarVertex*>(varscp->user1p());
        if (!vertexp) {
            UINFO(6, "New vertex " << varscp << endl);
            vertexp = new CdcVarVertex(&m_graph, m_scopep, varscp);
            varscp->user1p(vertexp);
            if (varscp->varp()->isUsedClock()) {}
            if (varscp->varp()->isPrimaryIO()) {
                // Create IO vertex - note it's relative to the pointed to var, not where we are
                // now This allows reporting to easily print the input statement
                CdcLogicVertex* ioVertexp
                    = new CdcLogicVertex(&m_graph, varscp->scopep(), varscp->varp(), nullptr);
                if (varscp->varp()->isWritable()) {
                    new V3GraphEdge(&m_graph, vertexp, ioVertexp, 1);
                } else {
                    new V3GraphEdge(&m_graph, ioVertexp, vertexp, 1);
                }
            }
        }
        if (m_inSenItem) {
            varscp->user2(true);  // It's like a clock...
            // TODO: In the future mark it here and do normal clock tree glitch checks also
        } else if (varscp->user2()) {  // It was detected in a sensitivity list earlier
            // And now it's used as logic.  So must be a reset.
            vertexp->cntAsyncRst(vertexp->cntAsyncRst() + 1);
        }
        return vertexp;
    }

    void warnAndFile(AstNode* nodep, V3ErrorCode code, const string& msg) {
        static bool told_file = false;
        nodep->v3warnCode(code, msg);
        if (!told_file) {
            told_file = true;
            std::cerr << V3Error::msgPrefix() << "     See details in " << m_ofFilename << endl;
        }
        *m_ofp << "%Warning-" << code.ascii() << ": " << nodep->fileline() << " " << msg << '\n';
    }

    void setNodeHazard(AstNode* nodep) {
        // Need to not clear if warnings are off (rather than when report it)
        // as bypassing this warning may turn up another path that isn't warning off'ed.
        // We can't modifyWarnOff here, as one instantiation might not be
        // an issue until we find a hitting flop.
        // Furthermore, a module like a "Or" module would only get flagged
        // once, even though the signals feeding it are radically different.
        if (!m_domainp || m_domainp->hasCombo()) {
            // Source flop logic in a posedge block is OK for reset (not async though)
            if (m_logicVertexp && !nodep->fileline()->warnIsOff(V3ErrorCode::CDCRSTLOGIC)) {
                UINFO(8, "Set hazard " << nodep << endl);
                m_logicVertexp->setHazard(nodep);
            }
        }
    }

    static string spaces(int level) {
        string out;
        while (level--) out += " ";
        return out;
    }  // LCOV_EXCL_LINE
    static string pad(unsigned column, const string& in) {
        string out = in;
        while (out.length() < column) out += ' ';
        return out;
    }

    void analyze() {
        UINFO(3, __FUNCTION__ << ": " << endl);
        // if (debug() > 6) m_graph.dump();
        if (debug() > 6) m_graph.dumpDotFilePrefixed("cdc_pre");
        //
        m_graph.removeRedundantEdges(
            &V3GraphEdge::followAlwaysTrue);  // This will MAX across edge weights
        //
        m_graph.dumpDotFilePrefixed("cdc_simp");
        //
        analyzeReset();
    }

    int filelineWidth() {
        if (!m_filelineWidth) {
            CdcWidthVisitor visitor(v3Global.rootp());
            m_filelineWidth = visitor.maxWidth();
        }
        return m_filelineWidth;
    }

    //----------------------------------------
    // RESET REPORT

    void analyzeReset() {
        // Find all async reset wires, and trace backwards
        // userClearVertices is very slow, so we use a generation count instead
        m_graph.userClearVertices();  // user1: uint32_t - was analyzed generation
        for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp = itp->verticesNextp()) {
            if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(itp)) {
                if (vvertexp->cntAsyncRst()) {
                    m_userGeneration++;  // Effectively a userClearVertices()
                    UINFO(8, "   Trace One async: " << vvertexp << endl);
                    // Twice, as we need to detect, then propagate
                    CdcEitherVertex* markp = traceAsyncRecurse(vvertexp, false);
                    if (markp) {  // Mark is non-nullptr if something bad on this path
                        UINFO(9, "   Trace One bad! " << vvertexp << endl);
                        m_userGeneration++;  // Effectively a userClearVertices()
                        traceAsyncRecurse(vvertexp, true);
                        m_userGeneration++;  // Effectively a userClearVertices()
                        dumpAsync(vvertexp, markp);
                    }
                }
            }
        }
    }

    CdcEitherVertex* traceAsyncRecurse(CdcEitherVertex* vertexp, bool mark) {
        // First pass: Return vertex of any hazardous stuff attached, or nullptr if OK
        // If first pass returns true, second pass calls asyncPath() on appropriate nodes
        if (vertexp->user() >= m_userGeneration) return nullptr;  // Processed - prevent loop
        vertexp->user(m_userGeneration);

        CdcEitherVertex* mark_outp = nullptr;
        UINFO(9, "      Trace: " << vertexp << endl);

        // Clear out in prep for marking next path
        if (!mark) vertexp->asyncPath(false);

        if (CdcLogicVertex* vvertexp = dynamic_cast<CdcLogicVertex*>(vertexp)) {
            // Any logic considered bad, at the moment, anyhow
            if (vvertexp->hazard() && !mark_outp) mark_outp = vvertexp;
            // And keep tracing back so the user can understand what's up
        } else if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(vertexp)) {
            if (mark) vvertexp->asyncPath(true);
            // If primary I/O, it's ok here back
            if (vvertexp->varScp()->varp()->isPrimaryInish()) {
                // Show the source "input" statement if it exists
                for (V3GraphEdge* edgep = vertexp->inBeginp(); edgep; edgep = edgep->inNextp()) {
                    CdcEitherVertex* eFromVertexp = static_cast<CdcEitherVertex*>(edgep->fromp());
                    eFromVertexp->asyncPath(true);
                }
                return nullptr;
            }
            // Also ok if from flop, but partially trace the flop so more obvious to users
            if (vvertexp->fromFlop()) {
                for (V3GraphEdge* edgep = vertexp->inBeginp(); edgep; edgep = edgep->inNextp()) {
                    CdcEitherVertex* eFromVertexp = static_cast<CdcEitherVertex*>(edgep->fromp());
                    eFromVertexp->asyncPath(true);
                }
                return nullptr;
            }
        }

        for (V3GraphEdge* edgep = vertexp->inBeginp(); edgep; edgep = edgep->inNextp()) {
            CdcEitherVertex* eFromVertexp = static_cast<CdcEitherVertex*>(edgep->fromp());
            CdcEitherVertex* submarkp = traceAsyncRecurse(eFromVertexp, mark);
            if (submarkp && !mark_outp) mark_outp = submarkp;
        }

        if (mark) vertexp->asyncPath(true);
        return mark_outp;
    }

    void dumpAsync(CdcVarVertex* vertexp, CdcEitherVertex* markp) {
        AstNode* nodep = vertexp->varScp();
        *m_ofp << "\n";
        *m_ofp << "\n";
        CdcEitherVertex* targetp = vertexp;  // One example destination flop (of possibly many)
        for (V3GraphEdge* edgep = vertexp->outBeginp(); edgep; edgep = edgep->outNextp()) {
            CdcEitherVertex* eToVertexp = static_cast<CdcEitherVertex*>(edgep->top());
            if (!eToVertexp) targetp = eToVertexp;
            if (CdcLogicVertex* vvertexp = dynamic_cast<CdcLogicVertex*>(eToVertexp)) {
                if (vvertexp->isFlop()  // IE the target flop that is upsetting us
                    && edgep->weight() >= CDC_WEIGHT_ASYNC) {  // And var feeds an async reset line
                    targetp = eToVertexp;
                    // UINFO(9," targetasync  "<<targetp->name()<<" "<<" from
                    // "<<vertexp->name()<<endl);
                    break;
                }
            }  // else it might be random logic that's not relevant
        }
        // UINFO(9," finalflop  "<<targetp->name()<<" "<<targetp->nodep()->fileline()<<endl);
        warnAndFile(markp->nodep(), V3ErrorCode::CDCRSTLOGIC,
                    "Logic in path that feeds async reset, via signal: " + nodep->prettyNameQ());
        dumpAsyncRecurse(targetp, "", "   ", 0);
    }
    bool dumpAsyncRecurse(CdcEitherVertex* vertexp, const string& prefix, const string& sep,
                          int level) {
        // level=0 is special, indicates to dump destination flop
        // Return true if printed anything
        // If mark, also mark the output even if nothing hazardous below
        if (vertexp->user() >= m_userGeneration) return false;  // Processed - prevent loop
        vertexp->user(m_userGeneration);
        if (!vertexp->asyncPath() && level != 0) return false;  // Not part of path

        // Other logic in the path
        string cont = prefix + sep;
        string nextsep = "   ";
        for (V3GraphEdge* edgep = vertexp->inBeginp(); edgep; edgep = edgep->inNextp()) {
            CdcEitherVertex* eFromVertexp = static_cast<CdcEitherVertex*>(edgep->fromp());
            if (dumpAsyncRecurse(eFromVertexp, cont, nextsep, level + 1)) nextsep = " | ";
        }

        // Dump single variable/logic block
        // See also OrderGraph::loopsVertexCb(V3GraphVertex* vertexp)
        AstNode* nodep = vertexp->nodep();
        string front
            = pad(filelineWidth(), nodep->fileline()->ascii() + ":") + " " + prefix + " +- ";
        if (VN_IS(nodep, VarScope)) {
            *m_ofp << front << "Variable: " << nodep->prettyName() << '\n';
        } else {
            V3EmitV::verilogPrefixedTree(nodep, *m_ofp, prefix + " +- ", filelineWidth(),
                                         vertexp->srcDomainp(), true);
            if (debug()) { CdcDumpVisitor visitor(nodep, m_ofp, front + "DBG: "); }
        }

        nextsep = " | ";
        if (level)
            *m_ofp << V3OutFile::indentSpaces(filelineWidth()) << " " << prefix << nextsep << "\n";

        if (CdcLogicVertex* vvertexp = dynamic_cast<CdcLogicVertex*>(vertexp)) {
            // Now that we've printed a path with this hazard, don't bother to print any more
            // Otherwise, we'd get a path for almost every destination flop
            vvertexp->clearHazard();
        }
        return true;
    }

    //----------------------------------------
    // EDGE REPORTS

    void edgeReport() {
        // Make report of all signal names and what clock edges they have
        //
        // Due to flattening, many interesting direct-connect signals are
        // lost, so we can't make a report showing I/Os for a low level
        // module.  Disabling flattening though makes us consider each
        // signal in it's own unique clock domain.

        UINFO(3, __FUNCTION__ << ": " << endl);

        // Trace all sources and sinks
        for (int traceDests = 0; traceDests < 2; ++traceDests) {
            UINFO(9, " Trace Direction " << (traceDests ? "dst" : "src") << endl);
            m_graph.userClearVertices();  // user1: bool - was analyzed
            for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp = itp->verticesNextp()) {
                if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(itp)) {
                    UINFO(9, "   Trace One edge: " << vvertexp << endl);
                    edgeDomainRecurse(vvertexp, traceDests, 0);
                }
            }
        }

        string filename = v3Global.opt.makeDir() + "/" + v3Global.opt.prefix() + "__cdc_edges.txt";
        const std::unique_ptr<std::ofstream> ofp(V3File::new_ofstream(filename));
        if (ofp->fail()) v3fatal("Can't write " << filename);
        *ofp << "Edge Report for " << v3Global.opt.prefix() << '\n';

        std::deque<string> report;  // Sort output by name
        for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp = itp->verticesNextp()) {
            if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(itp)) {
                AstVar* varp = vvertexp->varScp()->varp();
                {
                    string what = "wire";
                    if (varp->isPrimaryIO()) what = varp->direction().prettyName();

                    std::ostringstream os;
                    os.setf(std::ios::left);
                    // Module name - doesn't work due to flattening having lost the original
                    // so we assume the modulename matches the filebasename
                    string fname = vvertexp->varScp()->fileline()->filebasename() + ":";
                    os << "  " << std::setw(20) << fname;
                    os << "  " << std::setw(8) << what;
                    os << "  " << std::setw(40) << vvertexp->varScp()->prettyName();
                    os << "  SRC=";
                    if (vvertexp->srcDomainp()) {
                        V3EmitV::verilogForTree(vvertexp->srcDomainp(), os);
                    }
                    os << "  DST=";
                    if (vvertexp->dstDomainp()) {
                        V3EmitV::verilogForTree(vvertexp->dstDomainp(), os);
                    }
                    os << std::setw(0);
                    os << '\n';
                    report.push_back(os.str());
                }
            }
        }
        stable_sort(report.begin(), report.end());
        for (const auto& line : report) *ofp << line;
    }

    void edgeDomainRecurse(CdcEitherVertex* vertexp, bool traceDests, int level) {
        // Scan back to inputs/outputs, flops, and compute clock domain information
        UINFO(8, spaces(level) << "     Tracein  " << vertexp << endl);
        if (vertexp->user() >= m_userGeneration) return;  // Mid-Processed - prevent loop
        vertexp->user(m_userGeneration);

        // Variables from flops already are domained
        if (traceDests ? vertexp->dstDomainSet() : vertexp->srcDomainSet()) {
            return;
        }  // Fully computed

        std::set<AstSenTree*> senouts;  // List of all sensitivities for new signal
        if (CdcLogicVertex* vvertexp = dynamic_cast<CdcLogicVertex*>(vertexp)) {
            if (vvertexp) {}  // Unused
        } else if (CdcVarVertex* vvertexp = dynamic_cast<CdcVarVertex*>(vertexp)) {
            // If primary I/O, give it domain of the input
            AstVar* varp = vvertexp->varScp()->varp();
            if (varp->isPrimaryIO() && varp->isNonOutput() && !traceDests) {
                senouts.insert(new AstSenTree(
                    varp->fileline(), new AstSenItem(varp->fileline(), AstSenItem::Combo())));
            }
        }

        // Now combine domains of sources/dests
        if (traceDests) {
            for (V3GraphEdge* edgep = vertexp->outBeginp(); edgep; edgep = edgep->outNextp()) {
                CdcEitherVertex* eToVertexp = static_cast<CdcEitherVertex*>(edgep->top());
                edgeDomainRecurse(eToVertexp, traceDests, level + 1);
                if (eToVertexp->dstDomainp()) senouts.insert(eToVertexp->dstDomainp());
            }
        } else {
            for (V3GraphEdge* edgep = vertexp->inBeginp(); edgep; edgep = edgep->inNextp()) {
                CdcEitherVertex* eFromVertexp = static_cast<CdcEitherVertex*>(edgep->fromp());
                edgeDomainRecurse(eFromVertexp, traceDests, level + 1);
                if (eFromVertexp->srcDomainp()) senouts.insert(eFromVertexp->srcDomainp());
            }
        }

        // Convert list of senses into one sense node
        AstSenTree* senoutp = nullptr;
        bool senedited = false;
        for (const auto& itr : senouts) {
            if (!senoutp) {
                senoutp = itr;
            } else {
                if (!senedited) {
                    senedited = true;
                    senoutp = senoutp->cloneTree(true);
                }
                senoutp->addSensesp(itr->sensesp()->cloneTree(true));
            }
        }
        // If multiple domains need to do complicated optimizations
        if (senedited) senoutp = VN_CAST(V3Const::constifyExpensiveEdit(senoutp), SenTree);
        if (traceDests) {
            vertexp->dstDomainSet(true);  // Note it's set - domainp may be null, so can't use that
            vertexp->dstDomainp(senoutp);
            if (debug() >= 9) {
                UINFO(9, spaces(level) + "     Tracedst " << vertexp);
                if (senoutp) {
                    V3EmitV::verilogForTree(senoutp, cout);
                    cout << endl;
                }
            }
        } else {
            vertexp->srcDomainSet(true);  // Note it's set - domainp may be null, so can't use that
            vertexp->srcDomainp(senoutp);
            if (debug() >= 9) {
                UINFO(9, spaces(level) + "     Tracesrc " << vertexp);
                if (senoutp) {
                    V3EmitV::verilogForTree(senoutp, cout);
                    cout << endl;
                }
            }
        }
    }

    // VISITORS
    virtual void visit(AstNodeModule* nodep) override {
        VL_RESTORER(m_modp);
        {
            m_modp = nodep;
            iterateChildren(nodep);
        }
    }
    virtual void visit(AstScope* nodep) override {
        UINFO(4, " SCOPE " << nodep << endl);
        m_scopep = nodep;
        m_logicVertexp = nullptr;
        iterateChildren(nodep);
        m_scopep = nullptr;
    }
    virtual void visit(AstActive* nodep) override {
        // Create required blocks and add to module
        UINFO(4, "  BLOCK  " << nodep << endl);
        AstNode::user2ClearTree();
        m_domainp = nodep->sensesp();
        if (!m_domainp || m_domainp->hasCombo()
            || m_domainp->hasClocked()) {  // IE not hasSettle/hasInitial
            iterateNewStmt(nodep);
        }
        m_domainp = nullptr;
        AstNode::user2ClearTree();
    }
    virtual void visit(AstNodeVarRef* nodep) override {
        if (m_scopep) {
            UASSERT_OBJ(m_logicVertexp, nodep, "Var ref not under a logic block");
            AstVarScope* varscp = nodep->varScopep();
            UASSERT_OBJ(varscp, nodep, "Var didn't get varscoped in V3Scope.cpp");
            CdcVarVertex* varvertexp = makeVarVertex(varscp);
            UINFO(5, " VARREF to " << varscp << endl);
            // We use weight of one for normal edges,
            // Weight of CDC_WEIGHT_ASYNC to indicate feeds async (for reporting)
            // When simplify we'll take the MAX weight
            if (nodep->access().isWriteOrRW()) {
                new V3GraphEdge(&m_graph, m_logicVertexp, varvertexp, 1);
                if (m_inDly) {
                    varvertexp->fromFlop(true);
                    varvertexp->srcDomainp(m_domainp);
                    varvertexp->srcDomainSet(true);
                }
            } else {
                if (varvertexp->cntAsyncRst()) {
                    // UINFO(9," edgeasync "<<varvertexp->name()<<" to "<<m_logicVertexp<<endl);
                    new V3GraphEdge(&m_graph, varvertexp, m_logicVertexp, CDC_WEIGHT_ASYNC);
                } else {
                    // UINFO(9," edgena    "<<varvertexp->name()<<" to "<<m_logicVertexp<<endl);
                    new V3GraphEdge(&m_graph, varvertexp, m_logicVertexp, 1);
                }
            }
        }
    }
    virtual void visit(AstAssignDly* nodep) override {
        m_inDly = true;
        iterateChildren(nodep);
        m_inDly = false;
    }
    virtual void visit(AstSenItem* nodep) override {
        m_inSenItem = true;
        iterateChildren(nodep);
        m_inSenItem = false;
    }
    virtual void visit(AstAlways* nodep) override { iterateNewStmt(nodep); }
    virtual void visit(AstAlwaysPublic* nodep) override {
        // CDC doesn't care about public variables
    }
    virtual void visit(AstCFunc* nodep) override { iterateNewStmt(nodep); }
    virtual void visit(AstAssignAlias* nodep) override { iterateNewStmt(nodep); }
    virtual void visit(AstAssignW* nodep) override { iterateNewStmt(nodep); }

    // Math that shouldn't cause us to clear hazard
    virtual void visit(AstConst*) override {}
    virtual void visit(AstReplicate* nodep) override { iterateChildren(nodep); }
    virtual void visit(AstConcat* nodep) override { iterateChildren(nodep); }
    virtual void visit(AstNot* nodep) override { iterateChildren(nodep); }
    virtual void visit(AstSel* nodep) override {
        if (!VN_IS(nodep->lsbp(), Const)) setNodeHazard(nodep);
        iterateChildren(nodep);
    }
    virtual void visit(AstNodeSel* nodep) override {
        if (!VN_IS(nodep->bitp(), Const)) setNodeHazard(nodep);
        iterateChildren(nodep);
    }

    // Ignores
    virtual void visit(AstInitial*) override {}
    virtual void visit(AstTraceDecl*) override {}
    virtual void visit(AstCoverToggle*) override {}
    virtual void visit(AstNodeDType*) override {}

    //--------------------
    // Default
    virtual void visit(AstNodeMath* nodep) override {
        setNodeHazard(nodep);
        iterateChildren(nodep);
    }
    virtual void visit(AstNode* nodep) override { iterateChildren(nodep); }

public:
    // CONSTRUCTORS
    explicit CdcVisitor(AstNode* nodep) {
        // Make report of all signal names and what clock edges they have
        string filename = v3Global.opt.makeDir() + "/" + v3Global.opt.prefix() + "__cdc.txt";
        m_ofp = V3File::new_ofstream(filename);
        if (m_ofp->fail()) v3fatal("Can't write " << filename);
        m_ofFilename = filename;
        *m_ofp << "CDC Report for " << v3Global.opt.prefix() << '\n';
        *m_ofp
            << "Each dump below traces logic from inputs/source flops to destination flop(s).\n";
        *m_ofp << "First source logic is listed, then a variable that logic generates,\n";
        *m_ofp << "repeating recursively forwards to the destination flop(s).\n";
        *m_ofp << "%% Indicates the operator considered potentially hazardous.\n";

        iterate(nodep);
        analyze();
        if (debug() >= 1) edgeReport();  // Not useful to users at the moment
        if (false) {
            *m_ofp << "\nDBG-test-dumper\n";
            V3EmitV::verilogPrefixedTree(nodep, *m_ofp, "DBG ", 40, nullptr, true);
            *m_ofp << '\n';
        }
    }
    virtual ~CdcVisitor() override {
        if (m_ofp) VL_DO_CLEAR(delete m_ofp, m_ofp = nullptr);
    }
};

//######################################################################
// Cdc class functions

void V3Cdc::cdcAll(AstNetlist* nodep) {
    UINFO(2, __FUNCTION__ << ": " << endl);
    CdcVisitor visitor(nodep);
}