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Use unsigned in NFA, guard against overflow using V3Width. (#8152)

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Signed-off-by: Artur Bieniek <[email protected]>
This commit is contained in:
Artur Bieniek
2026-08-19 08:05:05 +02:00
committed by GitHub
parent f5ae58ddab
commit 06ee8b7261
8 changed files with 150 additions and 97 deletions
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src/V3Width.cpp
+53 -2
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@@ -744,15 +744,39 @@ class WidthVisitor final : public VNVisitor {
// it's like an if() condition.
iterateCheckBool(nodep, "default disable iff condition", nodep->condp(), BOTH);
}
static const AstConst* widthCheckSvaDelayBound(AstDelay* nodep, AstNodeExpr* boundp,
const char* what) {
const AstConst* const constp = VN_CAST(boundp, Const);
if (!constp || (constp->dtypep()->isSigned() && constp->num().isNegative())) {
nodep->v3error(what << " is not a non-negative elaboration-time constant"
" (IEEE 1800-2023 16.7)");
return nullptr;
}
if (constp->num().mostSetBitP1() > 31) {
nodep->v3warn(
E_UNSUPPORTED,
"Unsupported: SVA cycle delay exceeds implementation limit of 2147483647");
return nullptr;
}
return constp;
}
void visit(AstDelay* nodep) override {
if (nodep->isCycleDelay() && m_underSExpr) {
// Fold parameterized SVA cycle-delay bounds
userIterateAndNext(nodep->lhsp(), WidthVP{SELF, BOTH}.p());
V3Const::constifyParamsNoWarnEdit(nodep->lhsp());
const AstConst* const minConstp = widthCheckSvaDelayBound(
nodep, nodep->lhsp(),
nodep->isRangeDelay() ? "Range delay minimum" : "Delay value");
if (nodep->rhsp() && !nodep->isUnbounded()) {
// Fold parametrized SVA cycle-delay max bound
userIterateAndNext(nodep->rhsp(), WidthVP{SELF, BOTH}.p());
V3Const::constifyParamsNoWarnEdit(nodep->rhsp());
const AstConst* const maxConstp
= widthCheckSvaDelayBound(nodep, nodep->rhsp(), "Range delay maximum");
if (minConstp && maxConstp && maxConstp->toUInt() < minConstp->toUInt()) {
nodep->v3error("Range delay maximum must be >= minimum (IEEE 1800-2023 16.7)");
}
}
return;
}
@@ -1832,7 +1856,11 @@ class WidthVisitor final : public VNVisitor {
if (m_vup->prelim()) {
iterateCheckBool(nodep, "exprp", nodep->exprp(), BOTH);
userIterateAndNext(nodep->countp(), WidthVP{SELF, BOTH}.p());
if (nodep->maxCountp()) widthCheckGotoRepRange(nodep, "Goto");
if (nodep->maxCountp()) {
widthCheckGotoRepRange(nodep, "Goto");
} else {
widthCheckRepCount(nodep);
}
nodep->dtypeSetBit();
}
}
@@ -1841,10 +1869,33 @@ class WidthVisitor final : public VNVisitor {
if (m_vup->prelim()) {
iterateCheckBool(nodep, "exprp", nodep->exprp(), BOTH);
userIterateAndNext(nodep->countp(), WidthVP{SELF, BOTH}.p());
if (nodep->maxCountp()) widthCheckGotoRepRange(nodep, "Nonconsecutive");
if (nodep->maxCountp()) {
widthCheckGotoRepRange(nodep, "Nonconsecutive");
} else {
widthCheckRepCount(nodep);
}
nodep->dtypeSetBit();
}
}
template <typename T_Rep>
void widthCheckRepCount(T_Rep* nodep) {
V3Const::constifyParamsNoWarnEdit(nodep->countp());
const AstConst* const constp = VN_CAST(nodep->countp(), Const);
if (!constp) {
nodep->v3error("Repetition count is not an elaboration-time constant"
" (IEEE 1800-2023 16.9.2)");
} else if (constp->dtypep()->isSigned() && constp->num().isNegative()) {
nodep->v3error("Repetition count must be non-negative"
" (IEEE 1800-2023 16.9.2)");
} else if (constp->num().mostSetBitP1() > 31) {
nodep->v3warn(
E_UNSUPPORTED,
"Unsupported: SVA repetition count exceeds implementation limit of 2147483647");
} else if (constp->isZero()) {
nodep->v3warn(E_UNSUPPORTED, "Unsupported: zero repetition count"
" (IEEE 1800-2023 16.9.2)");
}
}
// IEEE 1800-2023 16.9.2 range-form bound validation for goto/nonconsec.
// Parent accessors are re-fetched after constifyParamsEdit because that
// call can replace the node in-tree (Lesson: AstSConsRep visitor pattern).