verilator/src/V3LinkLValue.cpp

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//*************************************************************************
// DESCRIPTION: Verilator: LValue module/signal name references
//
// Code available from: http://www.veripool.org/verilator
//
// AUTHORS: Wilson Snyder with Paul Wasson, Duane Gabli
//
//*************************************************************************
//
// Copyright 2003-2009 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.
//
// Verilator is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
//*************************************************************************
// LinkLValue TRANSFORMATIONS:
// Top-down traversal
// Set lvalue() attributes on appropriate VARREFs.
//*************************************************************************
#include "config_build.h"
#include "verilatedos.h"
#include <cstdio>
#include <cstdarg>
#include <unistd.h>
#include <map>
#include <algorithm>
#include <vector>
#include "V3Global.h"
#include "V3LinkLValue.h"
#include "V3Ast.h"
//######################################################################
// Link state, as a visitor of each AstNode
class LinkLValueVisitor : public AstNVisitor {
private:
// NODE STATE
// STATE
bool m_setRefLvalue; // Set VarRefs to lvalues for pin assignments
AstNodeFTask* m_ftaskp; // Function or task we're inside
// METHODS
static int debug() {
static int level = -1;
if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
return level;
}
// VISITs
// Result handing
virtual void visit(AstNodeVarRef* nodep, AstNUser*) {
// VarRef: LValue its reference
if (m_setRefLvalue) {
nodep->lvalue(true);
}
if (nodep->varp()) {
if (nodep->lvalue() && nodep->varp()->isInOnly()) {
if (!m_ftaskp) {
nodep->v3error("Assigning to input variable: "<<nodep->prettyName());
}
}
}
nodep->iterateChildren(*this);
}
// Nodes that start propagating down lvalues
virtual void visit(AstPin* nodep, AstNUser*) {
if (nodep->modVarp() && nodep->modVarp()->isOutput()) {
// When the varref's were created, we didn't know the I/O state
// Now that we do, and it's from a output, we know it's a lvalue
m_setRefLvalue = true;
nodep->iterateChildren(*this);
m_setRefLvalue = false;
} else {
nodep->iterateChildren(*this);
}
}
virtual void visit(AstNodeAssign* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->lhsp()->iterateAndNext(*this);
m_setRefLvalue = false;
nodep->rhsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFOpen* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
m_setRefLvalue = false;
nodep->filenamep()->iterateAndNext(*this);
nodep->modep()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFClose* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFFlush* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFGetC* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFGetS* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
nodep->strgp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstFScanF* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->filep()->iterateAndNext(*this);
nodep->exprsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstSScanF* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->exprsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstReadMem* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
m_setRefLvalue = true;
nodep->memp()->iterateAndNext(*this);
m_setRefLvalue = false;
nodep->filenamep()->iterateAndNext(*this);
nodep->lsbp()->iterateAndNext(*this);
nodep->msbp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
// Nodes that change LValue state
virtual void visit(AstSel* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{
nodep->lhsp()->iterateAndNext(*this);
// Only set lvalues on the from
m_setRefLvalue = false;
nodep->rhsp()->iterateAndNext(*this);
nodep->thsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstNodeSel* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{ // Only set lvalues on the from
nodep->lhsp()->iterateAndNext(*this);
m_setRefLvalue = false;
nodep->rhsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstNodePreSel* nodep, AstNUser*) {
bool last_setRefLvalue = m_setRefLvalue;
{ // Only set lvalues on the from
nodep->lhsp()->iterateAndNext(*this);
m_setRefLvalue = false;
nodep->rhsp()->iterateAndNext(*this);
nodep->thsp()->iterateAndNext(*this);
}
m_setRefLvalue = last_setRefLvalue;
}
virtual void visit(AstNodeFTask* nodep, AstNUser*) {
m_ftaskp = nodep;
nodep->iterateChildren(*this);
m_ftaskp = NULL;
}
virtual void visit(AstNodeFTaskRef* nodep, AstNUser*) {
AstNode* pinp = nodep->pinsp();
AstNodeFTask* taskp = nodep->taskp();
// We'll deal with mismatching pins later
if (!taskp) return;
for (AstNode* stmtp = taskp->stmtsp(); stmtp && pinp; stmtp=stmtp->nextp()) {
if (AstVar* portp = stmtp->castVar()) {
if (portp->isIO()) {
if (portp->isInput()) {
pinp->iterate(*this);
} else { // Output or Inout
m_setRefLvalue = true;
pinp->iterate(*this);
m_setRefLvalue = false;
}
// Advance pin
pinp = pinp->nextp();
}
}
}
}
virtual void visit(AstNode* nodep, AstNUser*) {
// Default: Just iterate
nodep->iterateChildren(*this);
}
public:
// CONSTUCTORS
LinkLValueVisitor(AstNode* nodep, bool start) {
m_setRefLvalue = start;
m_ftaskp = NULL;
nodep->accept(*this);
}
virtual ~LinkLValueVisitor() {}
};
//######################################################################
// Link class functions
void V3LinkLValue::linkLValue(AstNetlist* rootp) {
UINFO(4,__FUNCTION__<<": "<<endl);
LinkLValueVisitor visitor(rootp, false);
}
void V3LinkLValue::linkLValueSet(AstNode* nodep) {
// Called by later link functions when it is known a node needs
// to be converted to a lvalue.
UINFO(9,__FUNCTION__<<": "<<endl);
LinkLValueVisitor visitor(nodep, true);
}