forked from github/verilator
Internals: Some V3Tristate cleanups. No functional change.
This commit is contained in:
Wilson Snyder
parent
ff425369ac
commit
4135867e53
@ -51,7 +51,10 @@
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//
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// Note 1800-2012 adds user defined resolution functions. This suggests
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// long term this code should be scoped-based and resolve all nodes at once
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// rather than hierarchically.
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// rather than hierarchically. If/when that is done, make sure to avoid
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// duplicating vars and logic that is common between each instance of a
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// module.
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//
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//*************************************************************************
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#include "config_build.h"
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@ -235,10 +238,10 @@ public:
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}
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if (debug() >= 9) m_graph.dumpDotFilePrefixed("tri_pos__" + nodep->name());
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}
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void setTristate(AstNode* nodep) { makeVertex(nodep)->isTristate(true); }
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void associate(AstNode* fromp, AstNode* top) {
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new V3GraphEdge(&m_graph, makeVertex(fromp), makeVertex(top), 1);
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}
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void setTristate(AstNode* nodep) { makeVertex(nodep)->isTristate(true); }
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bool isTristate(AstNode* nodep) {
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const TristateVertex* const vertexp = reinterpret_cast<TristateVertex*>(nodep->user5p());
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return vertexp && vertexp->isTristate();
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@ -347,7 +350,7 @@ class TristateVisitor final : public TristateBaseVisitor {
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//
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AstNodeModule* m_modp = nullptr; // Current module
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AstCell* m_cellp = nullptr; // current cell
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VarMap m_lhsmap; // LHS driver map
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VarMap m_lhsmap; // Tristate left-hand-side driver map
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int m_unique = 0;
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bool m_alhs = false; // On LHS of assignment
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const AstNode* m_logicp = nullptr; // Current logic being built
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@ -362,67 +365,57 @@ class TristateVisitor final : public TristateBaseVisitor {
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if (m_alhs) o += "alhs ";
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return o;
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}
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void modAddStmtp(AstNode* nodep, AstNode* newp) {
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if (!m_modp) {
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nodep->v3warn(E_UNSUPPORTED,
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"Unsupported: Creating tristate signal not underneath a module: "
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<< nodep->prettyNameQ());
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} else {
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m_modp->addStmtp(newp);
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}
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}
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void associateLogic(AstNode* fromp, AstNode* top) {
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if (m_logicp) m_tgraph.associate(fromp, top);
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}
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AstNode* getEnp(AstNode* nodep) {
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// checks if user1p() is null, and if so, adds a constant output
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// enable driver of all 1's. Otherwise returns the user1p() data.
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if (!nodep->user1p()) {
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// There's no select being built yet, so add what will become a
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// constant output enable driver of all 1's
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V3Number num(nodep, nodep->width());
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num.setAllBits1();
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AstNode* const enp = new AstConst(nodep->fileline(), num);
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nodep->user1p(enp);
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}
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// Otherwise return the previous output enable
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return nodep->user1p();
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}
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AstVar* getCreateEnVarp(AstVar* invarp) {
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// Return the master __en for the specified input variable
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if (!invarp->user1p()) {
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AstVar* const newp = new AstVar(invarp->fileline(), AstVarType::MODULETEMP,
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invarp->name() + "__en", invarp);
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UINFO(9, " newenv " << newp << endl);
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if (!m_modp) {
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invarp->v3warn(E_UNSUPPORTED,
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"Unsupported: Creating tristate signal not underneath a module: "
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<< invarp->prettyNameQ());
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} else {
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m_modp->addStmtp(newp);
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}
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modAddStmtp(invarp, newp);
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invarp->user1p(newp); // find envar given invarp
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}
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return VN_AS(invarp->user1p(), Var);
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}
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AstVar* getCreateOutVarp(AstVar* invarp) {
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// Return the master __out for the specified input variable
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if (!invarp->user4p()) {
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AstVar* const newp = new AstVar(invarp->fileline(), AstVarType::MODULETEMP,
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invarp->name() + "__out", invarp);
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UINFO(9, " newout " << newp << endl);
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if (!m_modp) {
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invarp->v3warn(E_UNSUPPORTED,
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"Unsupported: Creating tristate signal not underneath a module: "
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<< invarp->prettyNameQ());
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} else {
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m_modp->addStmtp(newp);
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}
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modAddStmtp(invarp, newp);
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invarp->user4p(newp); // find outvar given invarp
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}
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return VN_AS(invarp->user4p(), Var);
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}
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AstVar* getCreateUnconnVarp(AstNode* fromp, AstNodeDType* dtypep) {
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AstVar* const newp = new AstVar(fromp->fileline(), AstVarType::MODULETEMP,
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"__Vtriunconn" + cvtToStr(m_unique++), dtypep);
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UINFO(9, " newunc " << newp << endl);
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if (!m_modp) {
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newp->v3warn(E_UNSUPPORTED,
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"Unsupported: Creating tristate signal not underneath a module");
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} else {
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m_modp->addStmtp(newp);
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}
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modAddStmtp(newp, newp);
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return newp;
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}
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@ -490,8 +483,8 @@ class TristateVisitor final : public TristateBaseVisitor {
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if (m_tgraph.isTristate(varp)) {
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const auto it = m_lhsmap.find(varp);
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if (it == m_lhsmap.end()) {
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// set output enable to always be off on this assign
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// statement so that this var is floating
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// This variable is floating, set output enable to
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// always be off on this assign
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UINFO(8, " Adding driver to var " << varp << endl);
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AstConst* const constp = new AstConst(
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varp->fileline(), AstConst::WidthedValue(), varp->width(), 0);
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@ -516,19 +509,23 @@ class TristateVisitor final : public TristateBaseVisitor {
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++nextit;
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AstVar* const invarp = it->first;
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const RefVec* const refsp = it->second;
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// Figure out if this var needs tristate expanded.
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if (!m_tgraph.isTristate(invarp)) {
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// This var has no tristate logic, so we leave it alone.
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if (m_tgraph.isTristate(invarp)) {
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insertTristatesSignal(nodep, invarp, refsp);
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} else {
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UINFO(8, " NO TRISTATE ON:" << invarp << endl);
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}
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// Delete the map and vector list now that we have expanded it.
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m_lhsmap.erase(invarp);
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VL_DO_DANGLING(delete refsp, refsp);
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continue;
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}
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}
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void insertTristatesSignal(AstNodeModule* nodep, AstVar* const invarp,
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const RefVec* const refsp) {
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UINFO(8, " TRISTATE EXPANDING:" << invarp << endl);
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++m_statTriSigs;
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m_tgraph.didProcess(invarp);
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UINFO(8, " TRISTATE EXPANDING:" << invarp << endl);
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// If the lhs var is a port, then we need to create ports for
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// the output (__out) and output enable (__en) signals. The
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@ -610,7 +607,7 @@ class TristateVisitor final : public TristateBaseVisitor {
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undrivenp = new AstConst(invarp->fileline(), ones);
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}
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if (!outvarp) {
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// This is the final resolution of the tristate, so we apply
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// This is the final pre-forced resolution of the tristate, so we apply
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// the pull direction to any undriven pins.
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V3Number pull(invarp, lhsp->width());
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const AstPull* const pullp = static_cast<AstPull*>(lhsp->user3p());
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@ -628,8 +625,7 @@ class TristateVisitor final : public TristateBaseVisitor {
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}
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if (envarp) {
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nodep->addStmtp(new AstAssignW(
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enp->fileline(), new AstVarRef(envarp->fileline(), envarp, VAccess::WRITE),
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enp));
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enp->fileline(), new AstVarRef(envarp->fileline(), envarp, VAccess::WRITE), enp));
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}
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// __out (child) or <in> (parent) = drive-value expression
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AstNode* const assp = new AstAssignW(
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@ -637,10 +633,6 @@ class TristateVisitor final : public TristateBaseVisitor {
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assp->user2(U2_BOTH); // Don't process further; already resolved
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if (debug() >= 9) assp->dumpTree(cout, "-lhsp-eqn: ");
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nodep->addStmtp(assp);
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// Delete the map and vector list now that we have expanded it.
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m_lhsmap.erase(invarp);
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VL_DO_DANGLING(delete refsp, refsp);
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}
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}
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// VISITORS
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@ -897,15 +889,15 @@ class TristateVisitor final : public TristateBaseVisitor {
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void visitAssign(AstNodeAssign* nodep) {
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if (m_graphing) {
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if (nodep->user2() & U2_GRAPHING) return;
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nodep->user2(U2_GRAPHING);
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VL_RESTORER(m_logicp);
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m_logicp = nodep;
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nodep->user2(U2_GRAPHING);
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iterateAndNextNull(nodep->rhsp());
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m_alhs = true;
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iterateAndNextNull(nodep->lhsp());
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m_alhs = false;
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associateLogic(nodep->rhsp(), nodep);
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associateLogic(nodep, nodep->lhsp());
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m_logicp = nullptr;
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} else {
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if (nodep->user2() & U2_NONGRAPH) {
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return; // Iterated here, or created assignment to ignore
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@ -1063,11 +1055,11 @@ class TristateVisitor final : public TristateBaseVisitor {
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nodep->v3warn(E_UNSUPPORTED, "Unsupported pullup/down (weak driver) construct.");
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} else {
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if (m_graphing) {
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varrefp->access(VAccess::WRITE);
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VL_RESTORER(m_logicp);
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m_logicp = nodep;
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varrefp->access(VAccess::WRITE);
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m_tgraph.setTristate(nodep);
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associateLogic(nodep, varrefp->varp());
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m_logicp = nullptr;
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} else {
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// Replace any pullup/pulldowns with assignw logic and set the
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// direction of the pull in the user3() data on the var. Given
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@ -1089,13 +1081,13 @@ class TristateVisitor final : public TristateBaseVisitor {
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void iteratePinGuts(AstPin* nodep) {
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if (m_graphing) {
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VL_RESTORER(m_logicp);
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m_logicp = nodep;
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if (nodep->exprp()) {
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associateLogic(nodep->exprp(), nodep);
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associateLogic(nodep, nodep->exprp());
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}
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iterateChildren(nodep);
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m_logicp = nullptr;
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} else {
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// All heavy lifting completed in graph visitor.
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if (nodep->exprp()) m_tgraph.didProcess(nodep);
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@ -1399,10 +1391,10 @@ class TristateVisitor final : public TristateBaseVisitor {
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}
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virtual void visit(AstCell* nodep) override {
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VL_RESTORER(m_cellp);
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m_cellp = nodep;
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m_alhs = false;
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iterateChildren(nodep);
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m_cellp = nullptr;
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}
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virtual void visit(AstNetlist* nodep) override { iterateChildrenBackwards(nodep); }
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