// VISITORS
virtual void visit(AstNodeVarRef* nodep, AstNUser*) {
if (nodep->varScopep() == m_elimVarScp) {
// Substitute in the new tree
// It's possible we substitute into something that will be reduced more later
// however, as we never delete the top Always/initial statement, all should be well.
m_didReplace = true;
if (nodep->lvalue()) nodep->v3fatalSrc("Can't replace lvalue assignments with const var");
AstNode* substp = m_replaceTreep->cloneTree(false);
if (nodep->castNodeVarRef()
&& substp->castNodeVarRef()
&& nodep->same(substp)) {
// Prevent a infinite loop...
substp->v3fatalSrc("Replacing node with itself; perhaps circular logic?");
}
// Which fileline() to use?
// If replacing with logic, an error/warning is likely to want to point to the logic
// IE what we're replacing with.
// However a VARREF should point to the original as it's otherwise confusing
// to throw warnings that point to a PIN rather than where the pin us used.
if (substp->castVarRef()) substp->fileline(nodep->fileline());
// Make the substp an rvalue like nodep. This facilitate the hashing in dedupe.
if (AstNodeVarRef* varrefp = substp->castNodeVarRef()) varrefp->lvalue(false);
nodep->replaceWith(substp);
nodep->deleteTree(); VL_DANGLING(nodep);
}
}
void V3Hashed::erase(iterator it) {
AstNode* nodep = iteratorNodep(it);
UINFO(8," erase "<<nodep<<endl);
if (!nodep->user4p()) nodep->v3fatalSrc("Called removeNode on non-hashed node");
m_hashMmap.erase(it);
nodep->user4p(NULL); // So we don't allow removeNode again
}
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;
}
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 != NULL);
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();
VL_DANGLING(nodep); // 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()->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,
prep->dtypep());
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
? static_cast<AstNode*>
(new AstAssignDly(fl, prep,
new AstVarRef(fl, varp, false)))
: static_cast<AstNode*>
(new AstAssign (fl, prep,
new AstVarRef(fl, varp, false)))),
NULL);
if (debug()>=9) newp->dumpTree(cout," _new: ");
abovep->addNextStmt(newp,abovep);
prep->user2p(newp); // Save so we may LogAnd it next time
}
}