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Support weight in coverage (#8472)

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This commit is contained in:
Marco Bartoli
2026-09-24 14:01:45 -04:00
committed by GitHub
parent 88082a4e96
commit 1aa5ab2e3a
40 changed files with 1132 additions and 283 deletions
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src/V3Width.cpp
+48 -1
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@@ -2075,6 +2075,32 @@ class WidthVisitor final : public VNVisitor {
assertAtExpr(nodep);
if (m_vup->prelim()) iterateCheckSizedSelf(nodep, "LHS", nodep->lhsp(), SELF, BOTH);
}
// Width a 'weight' coverage option as the signed 'int' member it sets (IEEE 1800-2023
// 19.10); a weight is a non-negative integral value, constant for type_option (19.7)
template <typename T_Option>
void widthCoverWeight(T_Option* nodep) {
iterateCheckSigned32(nodep, "weight", nodep->valuep(), BOTH);
V3Const::constifyEdit(nodep->valuep());
AstNodeExpr* const valuep = nodep->valuep();
const std::string optName
= std::string{nodep->typeOption() ? "type_option" : "option"} + ".weight";
if (const AstConst* const constp = VN_CAST(valuep, Const)) {
if (!constp->num().isNegative()) return;
valuep->v3error("Coverage option '" << optName << "' is set to negative value '"
<< constp->toSInt()
<< "'; weights must be non-negative"
" (IEEE 1800-2023 19.7)");
} else if (nodep->typeOption()) {
valuep->v3error("Coverage option '" << optName
<< "' requires a constant expression"
" (IEEE 1800-2023 19.7.1)");
} else {
return;
}
// Continue with the default weight
valuep->replaceWith(new AstConst{valuep->fileline(), AstConst::Signed32{}, 1});
VL_DO_DANGLING(pushDeletep(valuep), valuep);
}
void visit(AstCgOptionAssign* nodep) override {
// Recursive function widthing can reach a covergroup constructor without first visiting
// its class, so find the owning covergroup structurally instead of using visit context.
@@ -2082,6 +2108,12 @@ class WidthVisitor final : public VNVisitor {
UASSERT_OBJ(cgClassp && cgClassp->isCovergroup(), nodep,
"Covergroup option is not under a covergroup class");
// V3Covergroup stores the weight into the covergroup's option or type_option
if (nodep->optType() == VCoverOptionType::WEIGHT) {
widthCoverWeight(nodep);
return;
}
// Extract covergroup option values and store in AstClass before deleting.
if (nodep->optType() == VCoverOptionType::AUTO_BIN_MAX) {
// By V3Width time, V3Param has already folded any parameter references.
@@ -2094,12 +2126,27 @@ class WidthVisitor final : public VNVisitor {
nodep->valuep()->v3warn(COVERIGN, "Ignoring unsupported: non-constant "
"'option.auto_bin_max'; using default value");
}
} else if (nodep->optType() == VCoverOptionType::MERGE_INSTANCES) {
// get_coverage() always averages the instances (IEEE 1800-2023 19.11.3)
const AstConst* const constp = VN_CAST(nodep->valuep(), Const);
if (!constp || !constp->num().isEqZero()) {
nodep->v3warn(COVERIGN, "Ignoring unsupported: 'type_option.merge_instances';"
" type coverage is the weighted average of the"
" instances");
}
}
// Add more options here as needed (weight, goal, at_least, per_instance, comment)
// Add more options here as needed (goal, at_least, per_instance, comment)
// Delete the assignment node (we've extracted the value)
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
}
void visit(AstCoverOption* nodep) override {
if (nodep->optType() == VCoverOptionType::WEIGHT) {
widthCoverWeight(nodep);
return;
}
userIterateChildren(nodep, nullptr);
}
void visit(AstCoverCross* nodep) override {
userIterateAndNext(nodep->itemsp(), nullptr);
if (nodep->iffp()) iterateCheckBool(nodep, "iff condition", nodep->iffp(), BOTH);