void visit(AstSel* nodep, AstNUser*) {
nodep->iterateChildren(*this);
if (!nodep->user1Inc()) {
// Guard against reading/writing past end of bit vector array
int maxmsb = 0;
bool lvalue = false;
AstNode* basefromp = AstArraySel::baseFromp(nodep);
if (AstNodeVarRef* varrefp = basefromp->castNodeVarRef()) {
lvalue = varrefp->lvalue();
maxmsb = (varrefp->varp()->width()-1);
} else {
// If it's a PARAMETER[bit], then basefromp may be a constant instead of a varrefp
maxmsb = basefromp->width()-1;
}
int maxlsb = maxmsb - nodep->width() + 1;
if (debug()>=9) nodep->dumpTree(cout,"sel_old: ");
V3Number maxlsbnum (nodep->fileline(), nodep->lsbp()->width(), maxlsb);
// See if the condition is constant true
AstNode* condp = new AstLte (nodep->fileline(),
nodep->lsbp()->cloneTree(false),
new AstConst(nodep->fileline(), maxlsbnum));
// Note below has null backp(); the Edit function knows how to deal with that.
condp = V3Const::constifyEdit(condp);
if (condp->isOne()) {
// We don't need to add a conditional; we know the existing expression is ok
condp->deleteTree();
}
else if (!lvalue) {
// SEL(...) -> COND(LTE(bit<=maxlsb), ARRAYSEL(...), {width{1'bx}})
AstNRelinker replaceHandle;
nodep->unlinkFrBack(&replaceHandle);
V3Number xnum (nodep->fileline(), nodep->width());
xnum.setAllBitsX();
AstNode* newp = new AstCondBound (nodep->fileline(),
condp,
nodep,
new AstConst(nodep->fileline(), xnum));
if (debug()>=9) newp->dumpTree(cout," _new: ");
// Link in conditional
replaceHandle.relink(newp);
// Added X's, tristate them too
newp->accept(*this);
}
else { // lvalue
replaceBoundLvalue(nodep, condp);
}
}
}
void visitEqNeqWild(AstNodeBiop* nodep) {
UINFO(4," N/EQWILD->EQ "<<nodep<<endl);
V3Const::constifyEdit(nodep->lhsp()); // lhsp may change
V3Const::constifyEdit(nodep->rhsp()); // rhsp may change
if (nodep->lhsp()->castConst() && nodep->rhsp()->castConst()) {
// Both sides are constant, node can be constant
V3Const::constifyEdit(nodep); VL_DANGLING(nodep);
return;
} else {
AstNode* lhsp = nodep->lhsp()->unlinkFrBack();
AstNode* rhsp = nodep->rhsp()->unlinkFrBack();
AstNode* newp;
if (!rhsp->castConst()) {
nodep->v3error("Unsupported: RHS of ==? or !=? must be constant to be synthesizable"); // Says spec.
// Replace with anything that won't cause more errors
newp = new AstEq (nodep->fileline(), lhsp, rhsp);
} else {
// X or Z's become mask, ala case statements.
V3Number nummask (rhsp->fileline(), rhsp->width());
nummask.opBitsNonX(rhsp->castConst()->num());
V3Number numval (rhsp->fileline(), rhsp->width());
numval.opBitsOne (rhsp->castConst()->num());
AstNode* and1p = new AstAnd(nodep->fileline(), lhsp,
new AstConst(nodep->fileline(), nummask));
AstNode* and2p = new AstConst(nodep->fileline(), numval);
if (nodep->castEqWild())
newp = new AstEq (nodep->fileline(), and1p, and2p);
else newp = new AstNeq (nodep->fileline(), and1p, and2p);
rhsp->deleteTree(); VL_DANGLING(rhsp);
}
nodep->replaceWith(newp);
nodep->deleteTree(); VL_DANGLING(nodep);
// Iterate tree now that we may have gotten rid of the compare
newp->iterateChildren(*this);
}
}
virtual void visit(AstPin* nodep, AstNUser*) {
// PIN(p,expr) -> ASSIGNW(VARXREF(p),expr) (if sub's input)
// or ASSIGNW(expr,VARXREF(p)) (if sub's output)
UINFO(4," PIN "<<nodep<<endl);
if (!nodep->exprp()) return; // No-connect
if (debug()>=9) nodep->dumpTree(cout," Pin_oldb: ");
if (nodep->modVarp()->isOutOnly() && nodep->exprp()->castConst())
nodep->v3error("Output port is connected to a constant pin, electrical short");
// Use user1p on the PIN to indicate we created an assign for this pin
if (!nodep->user1SetOnce()) {
// Simplify it
V3Inst::pinReconnectSimple(nodep, m_cellp, m_modp, false);
// Make a ASSIGNW (expr, pin)
AstNode* exprp = nodep->exprp()->cloneTree(false);
if (exprp->width() != nodep->modVarp()->width())
nodep->v3fatalSrc("Width mismatch, should have been handled in pinReconnectSimple\n");
if (nodep->modVarp()->isInout()) {
nodep->v3fatalSrc("Unsupported: Verilator is a 2-state simulator");
} else if (nodep->modVarp()->isOutput()) {
AstNode* rhsp = new AstVarXRef (exprp->fileline(), nodep->modVarp(), m_cellp->name(), false);
AstAssignW* assp = new AstAssignW (exprp->fileline(), exprp, rhsp);
m_modp->addStmtp(assp);
} else if (nodep->modVarp()->isInput()) {
// Don't bother moving constants now,
// we'll be pushing the const down to the cell soon enough.
AstNode* assp = new AstAssignW
(exprp->fileline(),
new AstVarXRef(exprp->fileline(), nodep->modVarp(), m_cellp->name(), true),
exprp);
m_modp->addStmtp(assp);
if (debug()>=9) assp->dumpTree(cout," _new: ");
} else if (nodep->modVarp()->isIfaceRef()) {
// Create an AstAssignVarScope for Vars to Cells so we can link with their scope later
AstNode* lhsp = new AstVarXRef (exprp->fileline(), nodep->modVarp(), m_cellp->name(), false);
AstVarRef* refp = exprp->castVarRef();
if (!refp) exprp->v3fatalSrc("Interfaces: Pin is not connected to a VarRef");
AstAssignVarScope* assp = new AstAssignVarScope(exprp->fileline(), lhsp, refp);
m_modp->addStmtp(assp);
} else {
nodep->v3error("Assigned pin is neither input nor output");
}
}
// We're done with the pin
nodep->unlinkFrBack()->deleteTree(); nodep=NULL;
}
bool isCaseTreeFast(AstCase* nodep) {
int width = 0;
bool opaque = false;
m_caseItems = 0;
m_caseNoOverlapsAllCovered = true;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
for (AstNode* icondp = itemp->condsp(); icondp!=NULL; icondp=icondp->nextp()) {
if (icondp->width() > width) width = icondp->width();
if (icondp->isDouble()) opaque = true;
if (!icondp->castConst()) width = CASE_BARF; // Can't parse; not a constant
m_caseItems++;
}
}
m_caseWidth = width;
if (width==0 || width > CASE_OVERLAP_WIDTH || opaque) {
m_caseNoOverlapsAllCovered = false;
return false; // Too wide for analysis
}
UINFO(8,"Simple case statement: "<<nodep<<endl);
// Zero list of items for each value
for (uint32_t i=0; i<(1UL<<m_caseWidth); i++) m_valueItem[i] = NULL;
// Now pick up the values for each assignment
// We can cheat and use uint32_t's because we only support narrow case's
bool bitched = false;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
for (AstNode* icondp = itemp->condsp(); icondp!=NULL; icondp=icondp->nextp()) {
//if (debug()>=9) icondp->dumpTree(cout," caseitem: ");
AstConst* iconstp = icondp->castConst();
if (!iconstp) nodep->v3fatalSrc("above 'can't parse' should have caught this\n");
if (neverItem(nodep, iconstp)) {
// X in casez can't ever be executed
} else {
V3Number nummask (itemp->fileline(), iconstp->width());
nummask.opBitsNonX(iconstp->num());
uint32_t mask = nummask.toUInt();
V3Number numval (itemp->fileline(), iconstp->width());
numval.opBitsOne(iconstp->num());
uint32_t val = numval.toUInt();
for (uint32_t i=0; i<(1UL<<m_caseWidth); i++) {
if ((i & mask) == val) {
if (!m_valueItem[i]) {
m_valueItem[i] = itemp;
} else if (!itemp->ignoreOverlap() && !bitched) {
itemp->v3warn(CASEOVERLAP,"Case values overlap (example pattern 0x"<<hex<<i<<")");
bitched = true;
m_caseNoOverlapsAllCovered = false;
}
}
}
}
}
// Defaults were moved to last in the caseitem list by V3LinkDot
if (itemp->isDefault()) { // Case statement's default... Fill the table
for (uint32_t i=0; i<(1UL<<m_caseWidth); i++) {
if (!m_valueItem[i]) m_valueItem[i] = itemp;
}
}
}
for (uint32_t i=0; i<(1UL<<m_caseWidth); i++) {
if (!m_valueItem[i]) {
nodep->v3warn(CASEINCOMPLETE,"Case values incompletely covered (example pattern 0x"<<hex<<i<<")");
m_caseNoOverlapsAllCovered = false;
return false;
}
}
if (m_caseItems <= 3) return false; // Not worth simplifing
// Convert valueItem from AstCaseItem* to the expression
// Not done earlier, as we may now have a NULL because it's just a ";" NOP branch
for (uint32_t i=0; i<(1UL<<m_caseWidth); i++) {
m_valueItem[i] = m_valueItem[i]->castCaseItem()->bodysp();
}
return true; // All is fine
}
virtual void visit(AstAssignW* nodep, AstNUser*) {
// Note: this detects and expands tristates of the forms:
// assign x = (OE) ? y : 'hZ;
// assign x = (OE) ? 'hz : y;
// see if this a COND and separate out the __en logic from the output logic if it is
if (AstCond* condp = nodep->rhsp()->castCond()) {
//if (debug()>=9) nodep->dumpTree(cout,"- cond-in: ");
AstNode* oep = condp->condp();
AstNode* expr1p = condp->expr1p();
AstNode* expr2p = condp->expr2p();
AstNode* enrhsp;
AstNode* outrhsp;
if (expr1p->castConst() && expr1p->castConst()->num().isAllZ()) {
enrhsp = new AstNot(oep->fileline(), oep->unlinkFrBack());
outrhsp = expr2p->unlinkFrBack();
} else if (expr2p->castConst() && expr2p->castConst()->num().isAllZ()){
enrhsp = oep->unlinkFrBack();
outrhsp = expr1p->unlinkFrBack();
} else {
// not a tristate or not in a form we recgonize, so exit and move on.
return;
}
AstNode* outp = nodep->lhsp()->unlinkFrBack();;
AstVarRef* outrefp = NULL;
if (outp->castVarRef()) {
outrefp = outp->castVarRef();
} else if (outp->castSel()) {
outrefp = outp->castSel()->fromp()->castVarRef();
} else {
nodep->v3error("Can't find LHS varref");
}
createEnableVar(outp, outrefp, enrhsp, outrhsp->width());
// replace the old assign logic with the new one
AstAssignW* newassp = new AstAssignW(nodep->fileline(), outp,outrhsp);
//if (debug()>=9) newassp->dumpTreeAndNext(cout,"- cond-out: ");
nodep->replaceWith(newassp);
nodep->deleteTree(); nodep=NULL;
newassp->iterateChildren(*this);
}
// How about a tri gate?
else if (AstBufIf1* bufp = nodep->rhsp()->castBufIf1()) {
//if (debug()>=9) nodep->dumpTree(cout,"- tri-in : ");
AstNode* enrhsp = bufp->lhsp()->unlinkFrBack();
AstNode* outrhsp = bufp->rhsp()->unlinkFrBack();
AstNode* outp = nodep->lhsp()->unlinkFrBack();;
AstVarRef* outrefp = NULL;
if (outp->castVarRef()) {
outrefp = outp->castVarRef();
} else if (outp->castSel()) {
outrefp = outp->castSel()->fromp()->castVarRef();
} else {
nodep->v3error("Can't find LHS varref");
}
createEnableVar(outp, outrefp, enrhsp, outrhsp->width());
// replace the old assign logic with the new one
AstAssignW* newassp = new AstAssignW(nodep->fileline(), outp,outrhsp);
//if (debug()>=9) newassp->dumpTreeAndNext(cout,"- tri-out: ");
nodep->replaceWith(newassp);
nodep->deleteTree(); nodep=NULL;
newassp->iterateChildren(*this);
}
else {
nodep->iterateChildren(*this);
}
}
static AstAssignW* pinReconnectSimple(AstPin* pinp, AstCell* cellp, AstNodeModule*,
bool forTristate, bool alwaysCvt) {
// If a pin connection is "simple" leave it as-is
// Else create a intermediate wire to perform the interconnect
// Return the new assignment, if one was made
// Note this module calles cloneTree() via new AstVar
AstVar* pinVarp = pinp->modVarp();
AstVarRef* connectRefp = pinp->exprp()->castVarRef();
AstBasicDType* pinBasicp = pinVarp->dtypep()->basicp(); // Maybe NULL
AstBasicDType* connBasicp = NULL;
AstAssignW* assignp = NULL;
if (connectRefp) connBasicp = connectRefp->varp()->dtypep()->basicp();
//
if (!alwaysCvt
&& connectRefp
&& connectRefp->varp()->dtypep()->sameTree(pinVarp->dtypep())
&& !connectRefp->varp()->isSc()) { // Need the signal as a 'shell' to convert types
// Done. Same data type
} else if (!alwaysCvt
&& connectRefp
&& connectRefp->varp()->isIfaceRef()) {
// Done. Interface
} else if (!alwaysCvt
&& connBasicp
&& pinBasicp
&& connBasicp->width() == pinBasicp->width()
&& connBasicp->lsb() == pinBasicp->lsb()
&& !connectRefp->varp()->isSc() // Need the signal as a 'shell' to convert types
&& connBasicp->width() == pinVarp->width()
&& 1) {
// Done. One to one interconnect won't need a temporary variable.
} else if (!alwaysCvt && !forTristate && pinp->exprp()->castConst()) {
// Done. Constant.
} else {
// Make a new temp wire
//if (1||debug()>=9) { pinp->dumpTree(cout,"-in_pin:"); }
AstNode* pinexprp = pinp->exprp()->unlinkFrBack();
string newvarname = ((string)(pinVarp->isOutput() ? "__Vcellout" : "__Vcellinp")
+(forTristate?"t":"") // Prevent name conflict if both tri & non-tri add signals
+"__"+cellp->name()+"__"+pinp->name());
AstVar* newvarp = new AstVar (pinVarp->fileline(), AstVarType::MODULETEMP, newvarname, pinVarp);
// Important to add statement next to cell, in case there is a generate with same named cell
cellp->addNextHere(newvarp);
if (pinVarp->isInout()) {
pinVarp->v3fatalSrc("Unsupported: Inout connections to pins must be direct one-to-one connection (without any expression)");
} else if (pinVarp->isOutput()) {
// See also V3Inst
AstNode* rhsp = new AstVarRef(pinp->fileline(), newvarp, false);
UINFO(5,"pinRecon width "<<pinVarp->width()<<" >? "<<rhsp->width()<<" >? "<<pinexprp->width()<<endl);
rhsp = extendOrSel (pinp->fileline(), rhsp, pinVarp);
pinp->exprp(new AstVarRef (newvarp->fileline(), newvarp, true));
AstNode* rhsSelp = extendOrSel (pinp->fileline(), rhsp, pinexprp);
assignp = new AstAssignW (pinp->fileline(), pinexprp, rhsSelp);
} else {
// V3 width should have range/extended to make the widths correct
assignp = new AstAssignW (pinp->fileline(),
new AstVarRef(pinp->fileline(), newvarp, true),
pinexprp);
pinp->exprp(new AstVarRef (pinexprp->fileline(), newvarp, false));
}
if (assignp) cellp->addNextHere(assignp);
//if (debug()) { pinp->dumpTree(cout,"- out:"); }
//if (debug()) { assignp->dumpTree(cout,"- aout:"); }
}
return assignp;
}
virtual void visit(AstArraySel* nodep) {
nodep->iterateChildren(*this);
if (!nodep->user1SetOnce()) {
if (debug()==9) nodep->dumpTree(cout,"-in: ");
// Guard against reading/writing past end of arrays
AstNode* basefromp = AstArraySel::baseFromp(nodep->fromp());
bool lvalue = false;
if (AstNodeVarRef* varrefp = basefromp->castNodeVarRef()) {
lvalue = varrefp->lvalue();
} else if (basefromp->castConst()) {
// If it's a PARAMETER[bit], then basefromp may be a constant instead of a varrefp
} else {
nodep->v3fatalSrc("No VarRef or Const under ArraySel");
}
// Find range of dtype we are selecting from
int declElements = -1;
AstNodeDType* dtypep = nodep->fromp()->dtypep()->skipRefp();
if (!dtypep) nodep->v3fatalSrc("Select of non-selectable type");
if (AstNodeArrayDType* adtypep = dtypep->castNodeArrayDType()) {
declElements = adtypep->elementsConst();
} else {
nodep->v3error("Select from non-array "<<dtypep->prettyTypeName());
}
if (debug()>=9) nodep->dumpTree(cout,"arraysel_old: ");
V3Number widthnum (nodep->fileline(), nodep->bitp()->width(), declElements-1);
// See if the condition is constant true
AstNode* condp = new AstGte (nodep->fileline(),
new AstConst(nodep->fileline(), widthnum),
nodep->bitp()->cloneTree(false));
// Note below has null backp(); the Edit function knows how to deal with that.
condp = V3Const::constifyEdit(condp);
if (condp->isOne()) {
// We don't need to add a conditional; we know the existing expression is ok
condp->deleteTree();
}
else if (!lvalue
&& !nodep->backp()->castArraySel()) { // Too complicated and slow if mid-multidimension
// ARRAYSEL(...) -> COND(LT(bit<maxbit), ARRAYSEL(...), {width{1'bx}})
AstNRelinker replaceHandle;
nodep->unlinkFrBack(&replaceHandle);
V3Number xnum (nodep->fileline(), nodep->width());
if (nodep->isString()) {
xnum = V3Number(V3Number::String(), nodep->fileline(), "");
} else {
xnum.setAllBitsX();
}
AstNode* newp = new AstCondBound (nodep->fileline(),
condp,
nodep,
new AstConst(nodep->fileline(), xnum));
if (debug()>=9) newp->dumpTree(cout," _new: ");
// Link in conditional, can blow away temp xor
replaceHandle.relink(newp);
// Added X's, tristate them too
newp->accept(*this);
}
else if (!lvalue) { // Mid-multidimension read, just use zero
// ARRAYSEL(...) -> ARRAYSEL(COND(LT(bit<maxbit), bit, 0))
AstNRelinker replaceHandle;
AstNode* bitp = nodep->bitp()->unlinkFrBack(&replaceHandle);
V3Number zeronum (nodep->fileline(), bitp->width(), 0);
AstNode* newp = new AstCondBound (bitp->fileline(),
condp,
bitp,
new AstConst(bitp->fileline(), zeronum));
// Added X's, tristate them too
if (debug()>=9) newp->dumpTree(cout," _new: ");
replaceHandle.relink(newp);
newp->accept(*this);
}
else { // lvalue
replaceBoundLvalue(nodep, condp);
}
}
}
void V3Inst::pinReconnectSimple(AstPin* pinp, AstCell* cellp, AstNodeModule* modp) {
// If a pin connection is "simple" leave it as-is
// Else create a intermediate wire to perform the interconnect
// Note this module calles cloneTree() via new AstVar
AstVar* pinVarp = pinp->modVarp();
AstVarRef* connectRefp = pinp->exprp()->castVarRef();
AstBasicDType* pinBasicp = pinVarp->dtypep()->basicp(); // Maybe NULL
AstBasicDType* connBasicp = NULL;
if (connectRefp) connBasicp = connectRefp->varp()->dtypep()->basicp();
//
if (connectRefp
&& connectRefp->varp()->dtypep()->sameTree(pinVarp->dtypep())
&& !connectRefp->varp()->isSc()) { // Need the signal as a 'shell' to convert types
// Done. Same data type
} else if (connBasicp
&& pinBasicp
&& connBasicp->width() == pinBasicp->width()
&& connBasicp->lsb() == pinBasicp->lsb()
&& !connectRefp->varp()->isSc() // Need the signal as a 'shell' to convert types
&& pinp->width() == pinVarp->width()
&& 1) {
// Done. One to one interconnect won't need a temporary variable.
} else if (pinp->exprp()->castConst()) {
// Done. Constant.
} else {
// Make a new temp wire
//if (1||debug()>=9) { pinp->dumpTree(cout,"in_pin:"); }
AstAssignW* assignp = NULL;
AstNode* pinexprp = pinp->exprp()->unlinkFrBack();
string newvarname = "__Vcellinp__"+cellp->name()+"__"+pinp->name();
AstVar* newvarp = new AstVar (pinVarp->fileline(), AstVarType::MODULETEMP, newvarname, pinVarp);
modp->addStmtp(newvarp);
if (pinVarp->isInout()) {
pinVarp->v3fatalSrc("Unsupported: Inout connections to pins must be direct one-to-one connection (without any expression)");
} else if (pinVarp->isOutput()) {
// See also V3Inst
AstNode* rhsp = new AstVarRef(pinp->fileline(), newvarp, false);
if (pinp->width() > rhsp->width()) {
if (rhsp->isSigned()) {
rhsp = new AstExtendS(pinp->fileline(), rhsp);
} else {
rhsp = new AstExtend (pinp->fileline(), rhsp);
}
} else if (pinp->width() < rhsp->width()) {
rhsp = new AstSel (pinp->fileline(), rhsp, 0, pinp->width());
}
rhsp->widthSignedFrom(pinp);
assignp = new AstAssignW (pinp->fileline(), pinexprp, rhsp);
pinp->exprp(new AstVarRef (pinexprp->fileline(), newvarp, true));
} else {
// V3 width should have range/extended to make the widths correct
if (pinexprp->width() != pinVarp->width()) pinp->v3fatalSrc("Input pin width mismatch");
assignp = new AstAssignW (pinp->fileline(),
new AstVarRef(pinp->fileline(), newvarp, true),
pinexprp);
pinp->exprp(new AstVarRef (pinexprp->fileline(), newvarp, false));
}
pinp->widthSignedFrom(pinp->exprp());
if (assignp) modp->addStmtp(assignp);
//if (1||debug()) { pinp->dumpTree(cout," out:"); }
//if (1||debug()) { assignp->dumpTree(cout," aout:"); }
}
}
AstNode* createDlyArray(AstAssignDly* nodep, AstNode* lhsp) {
// Create delayed assignment
// See top of this file for transformation
// Return the new LHS for the assignment, Null = unlink
// Find selects
AstNode* newlhsp = NULL; // NULL = unlink old assign
AstSel* bitselp = NULL;
AstArraySel* arrayselp = NULL;
if (lhsp->castSel()) {
bitselp = lhsp->castSel();
arrayselp = bitselp->fromp()->castArraySel();
} else {
arrayselp = lhsp->castArraySel();
}
if (!arrayselp) nodep->v3fatalSrc("No arraysel under bitsel?");
if (arrayselp->length()!=1) nodep->v3fatalSrc("ArraySel with length!=1 should have been removed in V3Slice");
UINFO(4,"AssignDlyArray: "<<nodep<<endl);
//
//=== Dimensions: __Vdlyvdim__
deque<AstNode*> dimvalp; // Assignment value for each dimension of assignment
AstNode* dimselp=arrayselp;
for (; dimselp->castArraySel(); dimselp=dimselp->castArraySel()->fromp()) {
AstNode* valp = dimselp->castArraySel()->bitp()->unlinkFrBack();
dimvalp.push_front(valp);
}
AstVarRef* varrefp = dimselp->castVarRef();
if (!varrefp) nodep->v3fatalSrc("No var underneath arraysels\n");
if (!varrefp->varScopep()) varrefp->v3fatalSrc("Var didn't get varscoped in V3Scope.cpp\n");
varrefp->unlinkFrBack();
AstVar* oldvarp = varrefp->varp();
int modVecNum = oldvarp->user4(); oldvarp->user4(modVecNum+1);
//
deque<AstNode*> dimreadps; // Read value for each dimension of assignment
for (unsigned dimension=0; dimension<dimvalp.size(); dimension++) {
AstNode* dimp = dimvalp[dimension];
if (dimp->castConst()) { // bit = const, can just use it
dimreadps.push_front(dimp);
} else {
string bitvarname = (string("__Vdlyvdim")+cvtToStr(dimension)
+"__"+oldvarp->shortName()+"__v"+cvtToStr(modVecNum));
AstVarScope* bitvscp = createVarSc(varrefp->varScopep(), bitvarname, dimp->width());
AstAssign* bitassignp
= new AstAssign (nodep->fileline(),
new AstVarRef(nodep->fileline(), bitvscp, true),
dimp);
nodep->addNextHere(bitassignp);
dimreadps.push_front(new AstVarRef(nodep->fileline(), bitvscp, false));
}
}
//
//=== Bitselect: __Vdlyvlsb__
AstNode* bitreadp=NULL; // Code to read Vdlyvlsb
if (bitselp) {
AstNode* lsbvaluep = bitselp->lsbp()->unlinkFrBack();
if (bitselp->fromp()->castConst()) {// vlsb = constant, can just push constant into where we use it
bitreadp = lsbvaluep;
} else {
string bitvarname = (string("__Vdlyvlsb__")+oldvarp->shortName()+"__v"+cvtToStr(modVecNum));
AstVarScope* bitvscp = createVarSc(varrefp->varScopep(), bitvarname, lsbvaluep->width());
AstAssign* bitassignp = new AstAssign (nodep->fileline(),
new AstVarRef(nodep->fileline(), bitvscp, true),
lsbvaluep);
nodep->addNextHere(bitassignp);
bitreadp = new AstVarRef(nodep->fileline(), bitvscp, false);
}
}
//
//=== Value: __Vdlyvval__
AstNode* valreadp; // Code to read Vdlyvval
if (nodep->rhsp()->castConst()) { // vval = constant, can just push constant into where we use it
valreadp = nodep->rhsp()->unlinkFrBack();
} else {
string valvarname = (string("__Vdlyvval__")+oldvarp->shortName()+"__v"+cvtToStr(modVecNum));
AstVarScope* valvscp = createVarSc(varrefp->varScopep(), valvarname, nodep->rhsp()->width());
newlhsp = new AstVarRef(nodep->fileline(), valvscp, true);
valreadp = new AstVarRef(nodep->fileline(), valvscp, false);
}
//
//=== Setting/not setting boolean: __Vdlyvset__
AstVarScope* setvscp;
AstAssignPre* setinitp = NULL;
if (nodep->user3p()) {
// Simplistic optimization. If the previous statement in same scope was also a =>,
// then we told this nodep->user3 we can use its Vdlyvset rather than making a new one.
// This is good for code like:
// for (i=0; i<5; i++) vector[i] <= something;
setvscp = nodep->user3p()->castNode()->castVarScope();
++m_statSharedSet;
} else { // Create new one
string setvarname = (string("__Vdlyvset__")+oldvarp->shortName()+"__v"+cvtToStr(modVecNum));
setvscp = createVarSc(varrefp->varScopep(), setvarname, 1);
setinitp = new AstAssignPre (nodep->fileline(),
new AstVarRef(nodep->fileline(), setvscp, true),
new AstConst(nodep->fileline(), 0));
AstAssign* setassignp
= new AstAssign (nodep->fileline(),
new AstVarRef(nodep->fileline(), setvscp, true),
new AstConst(nodep->fileline(),
V3Number(nodep->fileline(),1,true)));
nodep->addNextHere(setassignp);
}
if (m_nextDlyp) { // Tell next assigndly it can share the variable
m_nextDlyp->user3p(setvscp);
}
//
// Create ALWAYSPOST for delayed variable
// We add all logic to the same block if it's for the same memory
// This insures that multiple assignments to the same memory will result
// in correctly ordered code - the last assignment must be last.
// It also has the nice side effect of assisting cache locality.
AstNode* selectsp = varrefp;
for (int dimension=int(dimreadps.size())-1; dimension>=0; --dimension) {
selectsp = new AstArraySel(nodep->fileline(), selectsp, dimreadps[dimension]);
}
if (bitselp) {
selectsp = new AstSel(nodep->fileline(), selectsp, bitreadp,
bitselp->widthp()->cloneTree(false));
}
// Build "IF (changeit) ...
UINFO(9," For "<<setvscp<<endl);
UINFO(9," & "<<varrefp<<endl);
AstAlwaysPost* finalp = varrefp->varScopep()->user4p()->castNode()->castAlwaysPost();
if (finalp) {
AstActive* oldactivep = finalp->user2p()->castNode()->castActive();
checkActivePost(varrefp, oldactivep);
if (setinitp) oldactivep->addStmtsp(setinitp);
} else { // first time we've dealt with this memory
finalp = new AstAlwaysPost(nodep->fileline(), NULL/*sens*/, NULL/*body*/);
UINFO(9," Created "<<finalp<<endl);
AstActive* newactp = createActivePost(varrefp);
newactp->addStmtsp(finalp);
varrefp->varScopep()->user4p(finalp);
finalp->user2p(newactp);
if (setinitp) newactp->addStmtsp(setinitp);
}
AstIf* postLogicp;
if (finalp->user3p()->castNode() == setvscp) {
// Optimize as above; if sharing Vdlyvset *ON SAME VARIABLE*,
// we can share the IF statement too
postLogicp = finalp->user4p()->castNode()->castIf();
if (!postLogicp) nodep->v3fatalSrc("Delayed assignment misoptimized; prev var found w/o associated IF");
} else {
postLogicp = new AstIf (nodep->fileline(),
new AstVarRef(nodep->fileline(), setvscp, false),
NULL,
NULL);
UINFO(9," Created "<<postLogicp<<endl);
finalp->addBodysp(postLogicp);
finalp->user3p(setvscp); // Remember IF's vset variable
finalp->user4p(postLogicp); // and the associated IF, as we may be able to reuse it
}
postLogicp->addIfsp(new AstAssign(nodep->fileline(), selectsp, valreadp));
return newlhsp;
}
void replaceBoundLvalue(AstNode* nodep, AstNode* condp) {
// Spec says a out-of-range LHS SEL results in a NOP.
// This is a PITA. We could:
// 1. IF(...) around an ASSIGN,
// but that would break a "foo[TOO_BIG]=$fopen(...)".
// 2. Hack to extend the size of the output structure
// by one bit, and write to that temporary, but never read it.
// That makes there be two widths() and is likely a bug farm.
// 3. Make a special SEL to choose between the real lvalue
// and a temporary NOP register.
// 4. Assign to a temp, then IF that assignment.
// This is suspected to be nicest to later optimizations.
// 4 seems best but breaks later optimizations. 3 was tried,
// but makes a mess in the emitter as lvalue switching is needed. So 4.
// SEL(...) -> temp
// if (COND(LTE(bit<=maxlsb))) ASSIGN(SEL(...)),temp)
if (m_assignwp) {
// Wire assigns must become always statements to deal with insertion
// of multiple statements. Perhaps someday make all wassigns into always's?
UINFO(5," IM_WireRep "<<m_assignwp<<endl);
m_assignwp->convertToAlways(); pushDeletep(m_assignwp); m_assignwp=NULL;
}
bool needDly = m_assigndlyp;
if (m_assigndlyp) {
// Delayed assignments become normal assignments,
// then the temp created becomes the delayed assignment
AstNode* newp = new AstAssign(m_assigndlyp->fileline(),
m_assigndlyp->lhsp()->unlinkFrBackWithNext(),
m_assigndlyp->rhsp()->unlinkFrBackWithNext());
m_assigndlyp->replaceWith(newp); pushDeletep(m_assigndlyp); m_assigndlyp=NULL;
}
AstNode* prep = nodep;
// Scan back to put the condlvalue above all selects (IE top of the lvalue)
while (prep->backp()->castNodeSel()
|| prep->backp()->castSel()) {
prep=prep->backp();
}
FileLine* fl = nodep->fileline();
nodep=NULL; // Zap it so we don't use it by mistake - use prep
// Already exists; rather than IF(a,... IF(b... optimize to IF(a&&b,
// Saves us teaching V3Const how to optimize, and it won't be needed again.
if (AstIf* ifp = prep->user2p()->castNode()->castIf()) {
if (needDly) prep->v3fatalSrc("Should have already converted to non-delay");
AstNRelinker replaceHandle;
AstNode* earliercondp = ifp->condp()->unlinkFrBack(&replaceHandle);
AstNode* newp = new AstLogAnd (condp->fileline(),
condp,
earliercondp);
UINFO(4, "Edit BOUNDLVALUE "<<newp<<endl);
replaceHandle.relink(newp);
}
else {
string name = ((string)"__Vlvbound"+cvtToStr(m_modp->varNumGetInc()));
AstVar* varp = new AstVar(fl, AstVarType::MODULETEMP, name,
AstLogicPacked(), prep->width());
m_modp->addStmtp(varp);
AstNode* abovep = prep->backp(); // Grab above point before lose it w/ next replace
prep->replaceWith(new AstVarRef(fl, varp, true));
AstNode* newp = new AstIf(fl, condp,
(needDly
? ((new AstAssignDly(fl, prep,
new AstVarRef(fl, varp, false)))->castNode())
: ((new AstAssign (fl, prep,
new AstVarRef(fl, varp, false)))->castNode())),
NULL);
if (debug()>=9) newp->dumpTree(cout," _new: ");
abovep->addNextStmt(newp,abovep);
prep->user2p(newp); // Save so we may LogAnd it next time
}
}
virtual void visit(AstArraySel* nodep, AstNUser*) {
nodep->iterateChildren(*this);
if (!nodep->user1Inc()) {
if (debug()==9) nodep->dumpTree(cout,"-in: ");
// Guard against reading/writing past end of arrays
AstNode* basefromp = AstArraySel::baseFromp(nodep->fromp());
int dimension = AstArraySel::dimension(nodep->fromp());
int maxmsb = 0;
bool lvalue = false;
if (AstNodeVarRef* varrefp = basefromp->castNodeVarRef()) {
AstArrayDType* adtypep = varrefp->varp()->dtypep()->dtypeDimensionp(dimension)->castArrayDType();
if (!adtypep) nodep->v3fatalSrc("ArraySel to type without array at same depth");
lvalue = varrefp->lvalue();
maxmsb = adtypep->elementsConst()-1;
} else if (AstConst* lhconstp = basefromp->castConst()) {
// If it's a PARAMETER[bit], then basefromp may be a constant instead of a varrefp
maxmsb = lhconstp->width();
} else {
nodep->v3fatalSrc("No VarRef or Const under ArraySel\n");
}
if (debug()>=9) nodep->dumpTree(cout,"arraysel_old: ");
V3Number widthnum (nodep->fileline(), nodep->bitp()->width(), maxmsb);
// See if the condition is constant true
AstNode* condp = new AstLte (nodep->fileline(),
nodep->bitp()->cloneTree(false),
new AstConst(nodep->fileline(), widthnum));
// Note below has null backp(); the Edit function knows how to deal with that.
condp = V3Const::constifyEdit(condp);
if (condp->isOne()) {
// We don't need to add a conditional; we know the existing expression is ok
condp->deleteTree();
}
else if (!lvalue
&& !nodep->backp()->castArraySel()) { // Too complicated and slow if mid-multidimension
// ARRAYSEL(...) -> COND(LT(bit<maxbit), ARRAYSEL(...), {width{1'bx}})
AstNRelinker replaceHandle;
nodep->unlinkFrBack(&replaceHandle);
V3Number xnum (nodep->fileline(), nodep->width());
xnum.setAllBitsX();
AstNode* newp = new AstCondBound (nodep->fileline(),
condp,
nodep,
new AstConst(nodep->fileline(), xnum));
if (debug()>=9) newp->dumpTree(cout," _new: ");
// Link in conditional, can blow away temp xor
replaceHandle.relink(newp);
// Added X's, tristate them too
newp->accept(*this);
}
else if (!lvalue) { // Mid-multidimension read, just use zero
// ARRAYSEL(...) -> ARRAYSEL(COND(LT(bit<maxbit), bit, 0))
AstNRelinker replaceHandle;
AstNode* bitp = nodep->bitp()->unlinkFrBack(&replaceHandle);
V3Number zeronum (nodep->fileline(), bitp->width(), 0);
AstNode* newp = new AstCondBound (bitp->fileline(),
condp,
bitp,
new AstConst(bitp->fileline(), zeronum));
// Added X's, tristate them too
if (debug()>=9) newp->dumpTree(cout," _new: ");
replaceHandle.relink(newp);
newp->accept(*this);
}
else { // lvalue
replaceBoundLvalue(nodep, condp);
}
}
}
