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328 lines
12 KiB
C++
328 lines
12 KiB
C++
// -*- mode: C++; c-file-style: "cc-mode" -*-
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//*************************************************************************
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// DESCRIPTION: Verilator: LValue module/signal name references
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//
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// Code available from: https://verilator.org
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//
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//*************************************************************************
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//
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// Copyright 2003-2023 by Wilson Snyder. This program is free software; you
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// can redistribute it and/or modify it under the terms of either the GNU
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// Lesser General Public License Version 3 or the Perl Artistic License
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// Version 2.0.
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// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
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//
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//*************************************************************************
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// LinkLValue TRANSFORMATIONS:
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// Top-down traversal
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// Set lvalue() attributes on appropriate VARREFs.
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//*************************************************************************
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#include "V3PchAstNoMT.h" // VL_MT_DISABLED_CODE_UNIT
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#include "V3LinkLValue.h"
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VL_DEFINE_DEBUG_FUNCTIONS;
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//######################################################################
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// Link state, as a visitor of each AstNode
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class LinkLValueVisitor final : public VNVisitor {
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// NODE STATE
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// STATE
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bool m_setContinuously = false; // Set that var has some continuous assignment
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bool m_setStrengthSpecified = false; // Set that var has assignment with strength specified.
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VAccess m_setRefLvalue; // Set VarRefs to lvalues for pin assignments
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// VISITs
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// Result handing
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void visit(AstNodeVarRef* nodep) override {
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// VarRef: LValue its reference
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if (m_setRefLvalue != VAccess::NOCHANGE) nodep->access(m_setRefLvalue);
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if (nodep->varp()) {
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if (nodep->access().isWriteOrRW() && m_setContinuously) {
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nodep->varp()->isContinuously(true);
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// Strength may only be specified in continuous assignment,
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// so it is needed to check only if m_setContinuously is true
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if (m_setStrengthSpecified) nodep->varp()->hasStrengthAssignment(true);
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}
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if (nodep->access().isWriteOrRW() && !nodep->varp()->isFuncLocal()
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&& nodep->varp()->isReadOnly()) {
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nodep->v3warn(ASSIGNIN,
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"Assigning to input/const variable: " << nodep->prettyNameQ());
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}
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}
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iterateChildren(nodep);
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}
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// Nodes that start propagating down lvalues
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void visit(AstPin* nodep) override {
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if (nodep->modVarp() && nodep->modVarp()->isWritable()) {
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// When the varref's were created, we didn't know the I/O state
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// Now that we do, and it's from a output, we know it's a lvalue
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m_setRefLvalue = VAccess::WRITE;
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iterateChildren(nodep);
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m_setRefLvalue = VAccess::NOCHANGE;
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} else {
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iterateChildren(nodep);
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}
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}
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void visit(AstNodeAssign* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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VL_RESTORER(m_setContinuously);
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{
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m_setRefLvalue = VAccess::WRITE;
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m_setContinuously = VN_IS(nodep, AssignW) || VN_IS(nodep, AssignAlias);
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if (AstAssignW* assignwp = VN_CAST(nodep, AssignW)) {
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if (assignwp->strengthSpecp()) m_setStrengthSpecified = true;
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}
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iterateAndNextNull(nodep->lhsp());
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m_setRefLvalue = VAccess::NOCHANGE;
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m_setContinuously = false;
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m_setStrengthSpecified = false;
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iterateAndNextNull(nodep->rhsp());
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}
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}
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void visit(AstRelease* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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VL_RESTORER(m_setContinuously);
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{
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m_setRefLvalue = VAccess::WRITE;
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m_setContinuously = false;
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iterateAndNextNull(nodep->lhsp());
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}
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}
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void visit(AstFireEvent* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->operandp());
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}
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}
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void visit(AstCastDynamic* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->fromp());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->top());
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}
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}
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void visit(AstFError* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->filep());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->strp());
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}
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}
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void visit(AstFGetS* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->filep());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->strgp());
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}
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}
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void visit(AstFRead* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->filep());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->memp());
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}
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}
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void visit(AstFScanF* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->filep());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->exprsp());
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}
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}
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void visit(AstFUngetC* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->filep());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->rhsp());
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}
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}
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void visit(AstSScanF* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->exprsp());
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}
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}
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void visit(AstSysIgnore* nodep) override {
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// Can't know if lvalue or not; presume not
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iterateChildren(nodep);
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}
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void visit(AstRand* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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if (!nodep->urandom()) m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->seedp());
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}
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}
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void visit(AstReadMem* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->memp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->filenamep());
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iterateAndNextNull(nodep->lsbp());
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iterateAndNextNull(nodep->msbp());
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}
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}
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void visit(AstTestPlusArgs* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->searchp());
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}
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}
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void visit(AstValuePlusArgs* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->searchp());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->outp());
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}
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}
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void visit(AstSFormat* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->lhsp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->fmtp());
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}
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}
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void visit(AstNodeDistBiop* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->lhsp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->rhsp());
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}
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void visit(AstNodeDistTriop* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->lhsp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->rhsp());
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iterateAndNextNull(nodep->thsp());
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}
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void prepost_visit(AstNodeTriop* nodep) {
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VL_RESTORER(m_setRefLvalue);
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{
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->lhsp());
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iterateAndNextNull(nodep->rhsp());
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m_setRefLvalue = VAccess::WRITE;
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iterateAndNextNull(nodep->thsp());
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}
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}
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void visit(AstPreAdd* nodep) override { prepost_visit(nodep); }
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void visit(AstPostAdd* nodep) override { prepost_visit(nodep); }
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void visit(AstPreSub* nodep) override { prepost_visit(nodep); }
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void visit(AstPostSub* nodep) override { prepost_visit(nodep); }
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// Nodes that change LValue state
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void visit(AstSel* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{
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iterateAndNextNull(nodep->fromp());
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// Only set lvalues on the from
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->lsbp());
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iterateAndNextNull(nodep->widthp());
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}
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}
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void visit(AstNodeSel* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{ // Only set lvalues on the from
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iterateAndNextNull(nodep->fromp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->bitp());
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}
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}
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void visit(AstCellArrayRef* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{ // selp is not an lvalue
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->selp());
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}
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}
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void visit(AstNodePreSel* nodep) override {
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VL_RESTORER(m_setRefLvalue);
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{ // Only set lvalues on the from
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iterateAndNextNull(nodep->fromp());
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m_setRefLvalue = VAccess::NOCHANGE;
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iterateAndNextNull(nodep->rhsp());
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iterateAndNextNull(nodep->thsp());
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}
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}
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void visit(AstMemberSel* nodep) override {
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if (m_setRefLvalue != VAccess::NOCHANGE) {
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nodep->access(m_setRefLvalue);
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} else {
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// It is the only place where the access is set to member select nodes.
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// If it doesn't have to be set to WRITE, it means that it is READ.
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nodep->access(VAccess::READ);
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}
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iterateChildren(nodep);
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}
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void visit(AstNodeFTaskRef* nodep) override {
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AstNode* pinp = nodep->pinsp();
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const AstNodeFTask* const taskp = nodep->taskp();
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// We'll deal with mismatching pins later
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if (!taskp) return;
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for (AstNode* stmtp = taskp->stmtsp(); stmtp && pinp; stmtp = stmtp->nextp()) {
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if (const AstVar* const portp = VN_CAST(stmtp, Var)) {
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if (portp->isIO()) {
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if (portp->isWritable()) {
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m_setRefLvalue = VAccess::WRITE;
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iterate(pinp);
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m_setRefLvalue = VAccess::NOCHANGE;
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} else {
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iterate(pinp);
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}
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// Advance pin
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pinp = pinp->nextp();
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}
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}
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}
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}
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void visit(AstNode* nodep) override { iterateChildren(nodep); }
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public:
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// CONSTRUCTORS
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LinkLValueVisitor(AstNode* nodep, VAccess start)
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: m_setRefLvalue{start} {
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iterate(nodep);
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}
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~LinkLValueVisitor() override = default;
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};
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//######################################################################
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// Link class functions
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void V3LinkLValue::linkLValue(AstNetlist* nodep) {
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UINFO(4, __FUNCTION__ << ": " << endl);
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{ LinkLValueVisitor{nodep, VAccess::NOCHANGE}; } // Destruct before checking
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V3Global::dumpCheckGlobalTree("linklvalue", 0, dumpTreeLevel() >= 6);
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}
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void V3LinkLValue::linkLValueSet(AstNode* nodep) {
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// Called by later link functions when it is known a node needs
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// to be converted to a lvalue.
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UINFO(9, __FUNCTION__ << ": " << endl);
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{ LinkLValueVisitor{nodep, VAccess::WRITE}; }
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}
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