virtual void visit(AstNodeCase* nodep, AstNUser*) {
if (nodep->castCase() && nodep->castCase()->casex()) {
nodep->v3warn(CASEX,"Suggest casez (with ?'s) in place of casex (with X's)");
}
// Detect multiple defaults
bool hitDefault = false;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
if (itemp->isDefault()) {
if (hitDefault) {
nodep->v3error("Multiple default statements in case statement.");
}
hitDefault = true;
}
}
// Check for X/Z in non-casex statements
{
m_caseExprp = nodep;
nodep->exprp()->accept(*this);
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
itemp->condsp()->iterateAndNext(*this);
}
m_caseExprp = NULL;
}
}
// VISITORS //========== Case assertions
virtual void visit(AstCase* nodep, AstNUser*) {
nodep->iterateChildren(*this);
if (!nodep->user1Inc()) {
bool has_default=false;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
if (itemp->isDefault()) has_default=true;
}
if (nodep->fullPragma() || nodep->priorityPragma()) {
// Simply need to add a default if there isn't one already
++m_statAsFull;
if (!has_default) {
nodep->addItemsp(new AstCaseItem(nodep->fileline(), NULL/*DEFAULT*/,
newFireAssert(nodep, "synthesis full_case, but non-match found")));
}
}
if (nodep->parallelPragma() || nodep->uniquePragma() || nodep->unique0Pragma()) {
// Need to check that one, and only one of the case items match at any moment
// If there's a default, we allow none to match, else exactly one must match
++m_statAsFull;
if (!has_default && !nodep->itemsp()) {
// Not parallel, but harmlessly so.
} else {
AstNode* propp = NULL;
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
for (AstNode* icondp = itemp->condsp(); icondp!=NULL; icondp=icondp->nextp()) {
AstNode* onep = new AstEq(icondp->fileline(),
nodep->exprp()->cloneTree(false),
icondp->cloneTree(false));
if (propp) propp = new AstConcat(icondp->fileline(), onep, propp);
else propp = onep;
}
}
bool allow_none = has_default || nodep->unique0Pragma();
AstNode* ohot = (allow_none
? (new AstOneHot0(nodep->fileline(), propp))->castNode()
: (new AstOneHot (nodep->fileline(), propp))->castNode());
AstIf* ifp = new AstIf (nodep->fileline(),
new AstLogNot (nodep->fileline(), ohot),
newFireAssert(nodep, "synthesis parallel_case, but multiple matches found"),
NULL);
ifp->branchPred(AstBranchPred::BP_UNLIKELY);
nodep->addNotParallelp(ifp);
}
}
}
}
virtual void visit(AstGenCase* nodep, AstNUser*) {
UINFO(9," GENCASE "<<nodep<<endl);
AstNode* keepp = NULL;
nodep->exprp()->iterateAndNext(*this);
V3Case::caseLint(nodep);
V3Width::widthParamsEdit(nodep); // Param typed widthing will NOT recurse the body,
// don't trigger errors yet.
V3Const::constifyParamsEdit(nodep->exprp()); // exprp may change
AstConst* exprp = nodep->exprp()->castConst();
// Constify
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
for (AstNode* ep = itemp->condsp(); ep; ) {
AstNode* nextp = ep->nextp(); //May edit list
ep->iterateAndNext(*this);
V3Const::constifyParamsEdit(ep); ep=NULL; // ep may change
// cppcheck-suppress redundantAssignment
ep = nextp;
}
}
// Item match
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
if (!itemp->isDefault()) {
for (AstNode* ep = itemp->condsp(); ep; ep=ep->nextp()) {
if (AstConst* ccondp = ep->castConst()) {
V3Number match (nodep->fileline(), 1);
match.opEq(ccondp->num(), exprp->num());
if (!keepp && match.isNeqZero()) {
keepp = itemp->bodysp();
}
} else {
itemp->v3error("Generate Case item does not evaluate to constant");
}
}
}
}
// Else default match
for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
if (itemp->isDefault()) {
if (!keepp) keepp=itemp->bodysp();
}
}
// Replace
if (keepp) {
keepp->unlinkFrBackWithNext();
nodep->replaceWith(keepp);
}
else nodep->unlinkFrBack();
nodep->deleteTree(); nodep=NULL;
}
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;
}
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
}
