virtual void visit(AstActive* nodep, AstNUser*) {
// Careful if adding variables here, ACTIVES can be under other ACTIVES
// Need to save and restore any member state in AstUntilStable block
if (!m_topScopep || !nodep->stmtsp()) {
// Not at the top or empty block...
// Only empty blocks should be leftover on the non-top. Killem.
if (nodep->stmtsp()) nodep->v3fatalSrc("Non-empty lower active");
nodep->unlinkFrBack()->deleteTree(); nodep=NULL;
} else {
UINFO(4," ACTIVE "<<nodep<<endl);
AstNode* stmtsp = nodep->stmtsp()->unlinkFrBackWithNext();
if (nodep->hasClocked()) {
// Remember the latest sensitivity so we can compare it next time
if (nodep->hasInitial()) nodep->v3fatalSrc("Initial block should not have clock sensitivity");
if (m_lastSenp && nodep->sensesp()->sameTree(m_lastSenp)) {
UINFO(4," sameSenseTree\n");
} else {
clearLastSen();
m_lastSenp = nodep->sensesp();
// Make a new if statement
m_lastIfp = makeActiveIf(m_lastSenp);
addToEvalLoop(m_lastIfp);
}
// Move statements to if
m_lastIfp->addIfsp(stmtsp);
} else if (nodep->hasInitial()) {
// Don't need to: clearLastSen();, as we're adding it to different cfunc
// Move statements to function
addToInitial(stmtsp);
} else if (nodep->hasSettle()) {
// Don't need to: clearLastSen();, as we're adding it to different cfunc
// Move statements to function
addToSettleLoop(stmtsp);
} else {
// Combo
clearLastSen();
// Move statements to function
addToEvalLoop(stmtsp);
}
nodep->unlinkFrBack()->deleteTree(); nodep = NULL;
}
}
virtual void visit(AstCoverToggle* nodep) {
//nodep->dumpTree(cout,"ct:");
//COVERTOGGLE(INC, ORIG, CHANGE) ->
// IF(ORIG ^ CHANGE) { INC; CHANGE = ORIG; }
AstNode* incp = nodep->incp()->unlinkFrBack();
AstNode* origp = nodep->origp()->unlinkFrBack();
AstNode* changep = nodep->changep()->unlinkFrBack();
AstIf* newp = new AstIf(nodep->fileline(),
new AstXor(nodep->fileline(),
origp,
changep),
incp, NULL);
// We could add another IF to detect posedges, and only increment if so.
// It's another whole branch though verus a potential memory miss.
// We'll go with the miss.
newp->addIfsp(new AstAssign(nodep->fileline(),
changep->cloneTree(false),
origp->cloneTree(false)));
nodep->replaceWith(newp); nodep->deleteTree(); VL_DANGLING(nodep);
}
void replaceCaseComplicated(AstCase* nodep) {
// CASEx(cexpr,ITEM(icond1,istmts1),ITEM(icond2,istmts2),ITEM(default,istmts3))
// -> IF((cexpr==icond1),istmts1,
// IF((EQ (AND MASK cexpr) (AND MASK icond1)
// ,istmts2, istmts3
AstNode* cexprp = nodep->exprp()->unlinkFrBack();
// We'll do this in two stages. First stage, convert the conditions to
// the appropriate IF AND terms.
if (debug()>=9) nodep->dumpTree(cout," _comp_IN: ");
bool hadDefault = false;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
if (!itemp->condsp()) {
// Default clause. Just make true, we'll optimize it away later
itemp->condsp(new AstConst(itemp->fileline(), AstConst::LogicTrue()));
hadDefault = true;
} else {
// Expressioned clause
AstNode* icondNextp = NULL;
AstNode* ifexprp = NULL; // If expression to test
for (AstNode* icondp = itemp->condsp(); icondp!=NULL; icondp=icondNextp) {
icondNextp = icondp->nextp();
icondp->unlinkFrBack();
AstNode* condp = NULL; // Default is to use and1p/and2p
AstConst* iconstp = icondp->castConst();
if (iconstp && neverItem(nodep, iconstp)) {
// X in casez can't ever be executed
icondp->deleteTree(); icondp=NULL; iconstp=NULL;
// For simplicity, make expression that is not equal, and let later
// optimizations remove it
condp = new AstConst(itemp->fileline(), AstConst::LogicFalse());
} else if (AstInsideRange* irangep = icondp->castInsideRange()) {
// Similar logic in V3Width::visit(AstInside)
AstNode* ap = AstGte::newTyped(itemp->fileline(),
cexprp->cloneTree(false),
irangep->lhsp()->unlinkFrBack());
AstNode* bp = AstLte::newTyped(itemp->fileline(),
cexprp->cloneTree(false),
irangep->rhsp()->unlinkFrBack());
condp = new AstAnd(itemp->fileline(), ap, bp);
} else if (iconstp && iconstp->num().isFourState()
&& (nodep->casex() || nodep->casez() || nodep->caseInside())) {
V3Number nummask (itemp->fileline(), iconstp->width());
nummask.opBitsNonX(iconstp->num());
V3Number numval (itemp->fileline(), iconstp->width());
numval.opBitsOne(iconstp->num());
AstNode* and1p = new AstAnd(itemp->fileline(), cexprp->cloneTree(false),
new AstConst(itemp->fileline(), nummask));
AstNode* and2p = new AstAnd(itemp->fileline(),
new AstConst(itemp->fileline(), numval),
new AstConst(itemp->fileline(), nummask));
icondp->deleteTree(); icondp=NULL; iconstp=NULL;
condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
} else {
// Not a caseX mask, we can simply build CASEEQ(cexpr icond)
AstNode* and1p = cexprp->cloneTree(false);
AstNode* and2p = icondp;
condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
}
if (!ifexprp) {
ifexprp = condp;
} else {
ifexprp = new AstLogOr(itemp->fileline(), ifexprp, condp);
}
}
// Replace expression in tree
itemp->condsp(ifexprp);
}
}
cexprp->deleteTree(); cexprp=NULL;
if (!hadDefault) {
// If there was no default, add a empty one, this greatly simplifies below code
// and constant propagation will just eliminate it for us later.
nodep->addItemsp(new AstCaseItem(nodep->fileline(),
new AstConst(nodep->fileline(), AstConst::LogicTrue()),
NULL));
}
if (debug()>=9) nodep->dumpTree(cout," _comp_COND: ");
// Now build the IF statement tree
// The tree can be quite huge. Pull ever group of 8 out, and make a OR tree.
// This reduces the depth for the bottom elements, at the cost of some of the top elements.
// If we ever have profiling data, we should pull out the most common item from here and
// instead make it the first IF branch.
int depth = 0;
AstNode* grouprootp = NULL;
AstIf* groupnextp = NULL;
AstIf* itemnextp = NULL;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
AstNode* istmtsp = itemp->bodysp(); // Maybe null -- no action.
if (istmtsp) istmtsp->unlinkFrBackWithNext();
// Expressioned clause
AstNode* ifexprp = itemp->condsp()->unlinkFrBack();
{ // Prepare for next group
if (++depth > CASE_ENCODER_GROUP_DEPTH) depth = 1;
if (depth == 1) { // First group or starting new group
itemnextp = NULL;
AstIf* newp = new AstIf(itemp->fileline(), ifexprp->cloneTree(true), NULL, NULL);
if (groupnextp) groupnextp->addElsesp(newp);
else grouprootp = newp;
groupnextp = newp;
} else { // Continue group, modify if condition to OR in this new condition
AstNode* condp = groupnextp->condp()->unlinkFrBack();
groupnextp->condp(new AstOr(ifexprp->fileline(),
condp,
ifexprp->cloneTree(true)));
}
}
{ // Make the new lower IF and attach in the tree
AstNode* itemexprp = ifexprp; ifexprp=NULL;
if (depth == (CASE_ENCODER_GROUP_DEPTH)) { // End of group - can skip the condition
itemexprp->deleteTree(); itemexprp=NULL;
itemexprp = new AstConst(itemp->fileline(), AstConst::LogicTrue());
}
AstIf* newp = new AstIf(itemp->fileline(), itemexprp, istmtsp, NULL);
if (itemnextp) itemnextp->addElsesp(newp);
else groupnextp->addIfsp(newp); // First in a new group
itemnextp = newp;
}
}
if (debug()>=9) nodep->dumpTree(cout," _comp_TREE: ");
// Handle any assertions
replaceCaseParallel(nodep, false);
// Replace the CASE... with IF...
if (debug()>=9) grouprootp->dumpTree(cout," _new: ");
if (grouprootp) nodep->replaceWith(grouprootp);
else nodep->unlinkFrBack();
nodep->deleteTree(); nodep=NULL;
}
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;
}
