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Support simple cycle delay sequence expressions inside assertion properties (#6508)

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Signed-off-by: Bartłomiej Chmiel <[email protected]>
Co-authored-by: Wilson Snyder <[email protected]>
This commit is contained in:
Bartłomiej Chmiel
2025-10-10 16:16:15 +02:00
committed by GitHub
co-authored by Wilson Snyder
parent 2ac7cf51a9
commit 31e73f1645
29 changed files with 1488 additions and 390 deletions
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src/V3Assert.cpp
+62 -24
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@@ -142,6 +142,7 @@ class AssertVisitor final : public VNVisitor {
VDouble0 m_statAsFull; // Statistic tracking
VDouble0 m_statPastVars; // Statistic tracking
bool m_inSampled = false; // True inside a sampled expression
bool m_inRestrict = false; // True inside restrict assertion
// METHODS
static AstNodeExpr* assertOnCond(FileLine* fl, VAssertType type,
@@ -274,6 +275,38 @@ class AssertVisitor final : public VNVisitor {
return newp;
}
static AstIf* assertCond(AstNodeCoverOrAssert* nodep, AstNodeExpr* propp, AstNode* passsp,
AstNode* failsp) {
AstIf* const ifp = new AstIf{nodep->fileline(), propp, passsp, failsp};
// It's more LIKELY that we'll take the nullptr if clause
// than the sim-killing else clause:
ifp->branchPred(VBranchPred::BP_LIKELY);
ifp->isBoundsCheck(true); // To avoid LATCH warning
return ifp;
}
static AstNode* assertBody(AstNodeCoverOrAssert* nodep, AstNodeExpr* propp, AstNode* passsp,
AstNode* failsp) {
if (AstPExpr* const pExpr = VN_CAST(propp, PExpr)) {
AstNodeExpr* const condp = pExpr->condp();
UASSERT_OBJ(condp, pExpr, "Should have condition");
AstIf* const ifp = assertCond(nodep, condp->unlinkFrBack(), passsp, failsp);
AstNode* const precondps = pExpr->precondp();
UASSERT_OBJ(precondps, pExpr, "Should have precondition");
precondps->unlinkFrBackWithNext()->addNext(ifp);
AstNodeStmt* const assertOnp
= newIfAssertOn(precondps, nodep->directive(), nodep->type());
AstFork* const forkp = new AstFork{precondps->fileline(), "", assertOnp};
forkp->joinType(VJoinType::JOIN_NONE);
return forkp;
}
AstIf* const ifp = assertCond(nodep, propp, passsp, failsp);
return newIfAssertOn(ifp, nodep->directive(), nodep->type());
}
AstNodeStmt* newFireAssertUnchecked(const AstNodeStmt* nodep, const string& message,
AstNodeExpr* exprsp = nullptr) {
// Like newFireAssert() but omits the asserts-on check
@@ -321,9 +354,7 @@ class AssertVisitor final : public VNVisitor {
}
}
//
AstNode* bodysp = nullptr;
bool selfDestruct = false;
AstIf* ifp = nullptr;
if (const AstCover* const snodep = VN_CAST(nodep, Cover)) {
++m_statCover;
if (!v3Global.opt.coverageUser()) {
@@ -334,14 +365,12 @@ class AssertVisitor final : public VNVisitor {
UASSERT_OBJ(covincp, snodep, "Missing AstCoverInc under assertion");
covincp->unlinkFrBackWithNext(); // next() might have AstAssign for trace
if (message != "") covincp->declp()->comment(message);
bodysp = covincp;
if (passsp) {
passsp = AstNode::addNext<AstNode, AstNode>(covincp, passsp);
} else {
passsp = covincp;
}
}
if (bodysp && passsp) bodysp = bodysp->addNext(passsp);
if (bodysp) bodysp = newIfAssertOn(bodysp, nodep->directive(), nodep->type());
ifp = new AstIf{nodep->fileline(), propp, bodysp};
ifp->isBoundsCheck(true); // To avoid LATCH warning
bodysp = ifp;
} else if (VN_IS(nodep, Assert) || VN_IS(nodep, AssertIntrinsic)) {
if (nodep->immediate()) {
++m_statAsImm;
@@ -349,33 +378,26 @@ class AssertVisitor final : public VNVisitor {
++m_statAsNotImm;
}
if (!passsp && !failsp) failsp = newFireAssertUnchecked(nodep, "'assert' failed.");
ifp = new AstIf{nodep->fileline(), propp, passsp, failsp};
ifp->isBoundsCheck(true); // To avoid LATCH warning
// It's more LIKELY that we'll take the nullptr if clause
// than the sim-killing else clause:
ifp->branchPred(VBranchPred::BP_LIKELY);
bodysp = newIfAssertOn(ifp, nodep->directive(), nodep->type());
} else {
nodep->v3fatalSrc("Unknown node type");
}
AstNode* bodysp = assertBody(nodep, propp, passsp, failsp);
if (sentreep) {
bodysp = new AstAlways{nodep->fileline(), VAlwaysKwd::ALWAYS, sentreep, bodysp};
}
if (passsp && !passsp->backp()) VL_DO_DANGLING(pushDeletep(passsp), passsp);
if (failsp && !failsp->backp()) VL_DO_DANGLING(pushDeletep(failsp), failsp);
AstNode* newp;
if (sentreep) {
newp = new AstAlways{nodep->fileline(), VAlwaysKwd::ALWAYS, sentreep, bodysp};
} else {
newp = bodysp;
}
// Install it
if (selfDestruct) {
// Delete it after making the tree. This way we can tell the user
// if it wasn't constructed nicely or has other errors without needing --coverage.
VL_DO_DANGLING(newp->deleteTree(), newp);
VL_DO_DANGLING(bodysp->deleteTree(), bodysp);
nodep->unlinkFrBack();
} else {
nodep->replaceWith(newp);
nodep->replaceWith(bodysp);
}
// Bye
VL_DO_DANGLING(pushDeletep(nodep), nodep);
@@ -579,6 +601,7 @@ class AssertVisitor final : public VNVisitor {
AstVar* const outvarp = new AstVar{
nodep->fileline(), VVarType::MODULETEMP,
"_Vpast_" + cvtToStr(m_modPastNum++) + "_" + cvtToStr(i), inp->dtypep()};
outvarp->lifetime(VLifetime::AUTOMATIC_EXPLICIT);
++m_statPastVars;
m_modp->addStmtsp(outvarp);
AstNode* const assp = new AstAssignDly{
@@ -605,7 +628,7 @@ class AssertVisitor final : public VNVisitor {
}
void visit(AstVarRef* nodep) override {
iterateChildren(nodep);
if (m_inSampled) {
if (m_inSampled && !VString::startsWith(nodep->name(), "__VpropPrecond")) {
if (!nodep->access().isReadOnly()) {
nodep->v3warn(E_UNSUPPORTED,
"Unsupported: Write to variable in sampled expression");
@@ -625,6 +648,19 @@ class AssertVisitor final : public VNVisitor {
m_inSampled = false;
iterateChildren(nodep);
}
void visit(AstPExpr* nodep) override {
{
VL_RESTORER(m_inSampled);
m_inSampled = false;
iterateAndNextNull(nodep->precondp());
}
iterate(nodep->condp());
if (!m_inRestrict) {
VL_DO_DANGLING(pushDeletep(nodep), nodep);
} else {
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
}
}
//========== Statements
void visit(AstDisplay* nodep) override {
@@ -790,6 +826,8 @@ class AssertVisitor final : public VNVisitor {
visitAssertionIterate(nodep, nullptr);
}
void visit(AstRestrict* nodep) override {
VL_RESTORER(m_inRestrict);
m_inRestrict = true;
iterateChildren(nodep);
// IEEE says simulator ignores these
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);