luke/verilator
1
0
Fork 0
mirror of https://github.com/verilator/verilator.git synced 2026-10-06 10:03:44 +02:00
Code Issues Packages Projects Releases Wiki Activity

Fix output clockvar overwriting signal (#5320) (#5347)

Browse Source 
Signed-off-by: Krzysztof Bieganski <[email protected]>
This commit is contained in:
Krzysztof Bieganski
2024-08-08 21:48:25 +01:00
committed by GitHub
parent 004865a8b2
commit 701fa5438a
3 changed files with 117 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/V3AssertPre.cpp
+34 -5
View File
@@ -182,18 +182,47 @@ private:
m_clockingp->addNextHere(varp->unlinkFrBack());
varp->user1p(nodep);
if (nodep->direction() == VDirection::OUTPUT) {
AstVarRef* const skewedRefp = new AstVarRef{flp, varp, VAccess::READ};
skewedRefp->user1(true);
AstAssign* const assignp = new AstAssign{flp, exprp->cloneTreePure(false), skewedRefp};
exprp->foreach([](AstNodeVarRef* varrefp) {
// Prevent confusing BLKANDNBLK warnings on clockvars due to generated assignments
varrefp->fileline()->warnOff(V3ErrorCode::BLKANDNBLK, true);
});
AstVarRef* const skewedReadRefp = new AstVarRef{flp, varp, VAccess::READ};
skewedReadRefp->user1(true);
// Initialize the clockvar
AstVarRef* const skewedWriteRefp = new AstVarRef{flp, varp, VAccess::WRITE};
skewedWriteRefp->user1(true);
AstInitialStatic* const initClockvarp = new AstInitialStatic{
flp, new AstAssign{flp, skewedWriteRefp, exprp->cloneTreePure(false)}};
m_modp->addStmtsp(initClockvarp);
// A var to keep the previous value of the clockvar
AstVar* const prevVarp = new AstVar{
flp, VVarType::MODULETEMP, "__Vclocking_prev__" + varp->name(), exprp->dtypep()};
prevVarp->lifetime(VLifetime::STATIC);
AstInitialStatic* const initPrevClockvarp = new AstInitialStatic{
flp, new AstAssign{flp, new AstVarRef{flp, prevVarp, VAccess::WRITE},
skewedReadRefp->cloneTreePure(false)}};
m_modp->addStmtsp(prevVarp);
m_modp->addStmtsp(initPrevClockvarp);
// Assign the clockvar to the actual var; only do it if the clockvar's value has
// changed
AstAssign* const assignp
= new AstAssign{flp, exprp->cloneTreePure(false), skewedReadRefp};
AstIf* const ifp
= new AstIf{flp,
new AstNeq{flp, new AstVarRef{flp, prevVarp, VAccess::READ},
skewedReadRefp->cloneTreePure(false)},
assignp};
ifp->addThensp(new AstAssign{flp, new AstVarRef{flp, prevVarp, VAccess::WRITE},
skewedReadRefp->cloneTree(false)});
if (skewp->isZero()) {
// Drive the var in Re-NBA (IEEE 1800-2023 14.16)
m_clockingp->addNextHere(new AstAlwaysReactive{
flp, new AstSenTree{flp, m_clockingp->sensesp()->cloneTree(false)}, assignp});
flp, new AstSenTree{flp, m_clockingp->sensesp()->cloneTree(false)}, ifp});
} else if (skewp->fileline()->timingOn()) {
// Create a fork so that this AlwaysObserved can be retriggered before the
// assignment happens. Also then it can be combo, avoiding the need for creating
// new triggers.
AstFork* const forkp = new AstFork{flp, "", assignp};
AstFork* const forkp = new AstFork{flp, "", ifp};
forkp->joinType(VJoinType::JOIN_NONE);
// Use Observed for this to make sure we do not miss the event
m_clockingp->addNextHere(new AstAlwaysObserved{