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Support dynamic array .size in inline randomize() with constraints (#7258) (#7266)

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This commit is contained in:
Yilou Wang
2026-03-16 18:48:36 -04:00
committed by GitHub
parent be0f4a507e
commit d57324e5fb
4 changed files with 184 additions and 18 deletions
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src/V3Randomize.cpp
+92 -15
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@@ -3572,6 +3572,32 @@ class RandomizeVisitor final : public VNVisitor {
UASSERT_OBJ(VN_IS(exprp, VarRef), exprp, "Should be a VarRef");
return new AstVarRef{exprp->fileline(), VN_AS(varp->user2p(), Class), varp, access};
}
// Get or create a size variable for a constrained dynamic/queue/assoc array.
// Returns the size variable. Sets wasCreated=true if a new variable was made.
AstVar* createOrGetSizeVar(AstClass* const classp, AstVar* const arrVarp, FileLine* const fl,
AstNodeDType* const signed32DTypep, bool& wasCreated) {
AstVar* sizeVarp = VN_CAST(arrVarp->user4p(), Var);
wasCreated = false;
if (!sizeVarp) {
sizeVarp = new AstVar{fl, VVarType::BLOCKTEMP, "__V" + arrVarp->name() + "_size",
signed32DTypep};
classp->addMembersp(sizeVarp);
m_memberMap.insert(classp, sizeVarp);
sizeVarp->user2p(classp);
arrVarp->user4p(sizeVarp);
wasCreated = true;
}
return sizeVarp;
}
// Build a size >= 0 constraint expression (signed int size must be non-negative).
// Returns a new AstConstraintExpr with user1 bits set for solver visibility.
AstConstraintExpr* createSizeGteZeroConstraint(FileLine* const fl, AstVar* const sizeVarp) {
AstVarRef* const sizeVarRefp = new AstVarRef{fl, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);
AstGteS* const sizeGtep = new AstGteS{fl, sizeVarRefp, new AstConst{fl, 0}};
sizeGtep->user1(true);
return new AstConstraintExpr{fl, sizeGtep};
}
AstNodeExpr* getFromp(AstNodeExpr* const exprp) {
if (AstMemberSel* const memberSelp = VN_CAST(exprp, MemberSel)) {
return memberSelp->fromp();
@@ -4719,6 +4745,57 @@ class RandomizeVisitor final : public VNVisitor {
// Generate constraint setup code and a hardcoded call to the solver
AstNode* const capturedTreep = withp->exprp()->unlinkFrBackWithNext();
randomizeFuncp->addStmtsp(capturedTreep);
// Pre-scan captured tree for .size on dynamic/assoc arrays and replace
// with size variables, using shared createOrGetSizeVar helper.
// After CaptureVisitor, fromp() of .size is AstMemberSel (not VarRef),
// so extract the underlying variable from the MemberSel chain.
// Collect resize statements to add after solver call, guarded by success.
AstNode* inlineResizeStmtsp = nullptr;
{
std::vector<AstCMethodHard*> sizeMethodps;
capturedTreep->foreachAndNext([&](AstCMethodHard* methodp) {
if (methodp->method() == VCMethod::DYN_SIZE
|| methodp->method() == VCMethod::ASSOC_SIZE) {
sizeMethodps.push_back(methodp);
}
});
for (AstCMethodHard* const methodp : sizeMethodps) {
// Extract array variable from fromp (VarRef or MemberSel after capture)
AstVar* arrVarp = nullptr;
if (AstVarRef* const varRefp = VN_CAST(methodp->fromp(), VarRef)) {
arrVarp = varRefp->varp();
} else if (AstMemberSel* const memberSelp = VN_CAST(methodp->fromp(), MemberSel)) {
arrVarp = memberSelp->varp();
}
if (!arrVarp) continue;
// Only handle rand-declared dynamic/assoc array variables
if (!arrVarp->rand().isRandomizable()) continue;
FileLine* const fl = methodp->fileline();
bool wasCreated = false;
AstVar* const sizeVarp = createOrGetSizeVar(
classp, arrVarp, fl, methodp->findSigned32DType(), wasCreated);
if (wasCreated) {
// Generate resize for dynamic arrays/queues (not assoc arrays)
if (!VN_IS(arrVarp->dtypep()->skipRefp(), AssocArrayDType)) {
AstCMethodHard* const resizep = new AstCMethodHard{
fl, new AstVarRef{fl, classp, arrVarp, VAccess::READWRITE},
VCMethod::DYN_RESIZE, new AstVarRef{fl, sizeVarp, VAccess::READ}};
resizep->dtypep(methodp->findVoidDType());
inlineResizeStmtsp
= AstNode::addNext(inlineResizeStmtsp, new AstStmtExpr{fl, resizep});
}
// Append size >= 0 constraint so ConstraintExprVisitor processes it
capturedTreep->addNext(createSizeGteZeroConstraint(fl, sizeVarp));
}
AstVarRef* const sizeVarRefp = new AstVarRef{fl, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);
methodp->replaceWith(sizeVarRefp);
VL_DO_DANGLING(methodp->deleteTree(), methodp);
}
}
{
expandUniqueElementList(capturedTreep);
ConstraintExprVisitor{classp, m_memberMap, capturedTreep, randomizeFuncp,
@@ -4735,6 +4812,16 @@ class RandomizeVisitor final : public VNVisitor {
new AstVarRef{nodep->fileline(), VN_AS(randomizeFuncp->fvarp(), Var), VAccess::WRITE},
new AstAnd{nodep->fileline(), basicRandomizeFuncCallp, solverCallp}});
// Resize constrained arrays only when solver succeeds, mirroring
// the class-level if(__Vsize_ok) guard pattern
if (inlineResizeStmtsp) {
AstVar* const retVarp = VN_AS(randomizeFuncp->fvarp(), Var);
AstIf* const ifp = new AstIf{nodep->fileline(),
new AstVarRef{nodep->fileline(), retVarp, VAccess::READ},
inlineResizeStmtsp, nullptr};
randomizeFuncp->addStmtsp(ifp);
}
// Call nested post_randomize on rand class-type members (IEEE 18.4.1)
if (classHasRandClassMembers(classp)) {
AstTask* const postTaskp = getCreateNestedCallbackTask(classp, "post");
@@ -4774,16 +4861,10 @@ class RandomizeVisitor final : public VNVisitor {
return;
}
AstVar* const queueVarp = queueVarRefp->varp();
AstVar* sizeVarp = VN_CAST(queueVarp->user4p(), Var);
if (!sizeVarp) {
sizeVarp = new AstVar{fl, VVarType::BLOCKTEMP, "__V" + queueVarp->name() + "_size",
nodep->findSigned32DType()};
classp->addMembersp(sizeVarp);
m_memberMap.insert(classp, sizeVarp);
sizeVarp->user2p(classp);
queueVarp->user4p(sizeVarp);
bool wasCreated = false;
AstVar* const sizeVarp = createOrGetSizeVar(classp, queueVarp, fl,
nodep->findSigned32DType(), wasCreated);
if (wasCreated) {
// Associative arrays have no resize(); only generate resize
// for dynamic arrays and queues
if (!VN_IS(queueVarp->dtypep()->skipRefp(), AssocArrayDType)) {
@@ -4802,11 +4883,7 @@ class RandomizeVisitor final : public VNVisitor {
// Since size variable is signed int, we need additional constraint
// to make sure it is always >= 0.
AstVarRef* const sizeVarRefp = new AstVarRef{fl, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);
AstGteS* const sizeGtep = new AstGteS{fl, sizeVarRefp, new AstConst{fl, 0}};
sizeGtep->user1(true);
m_constraintp->addItemsp(new AstConstraintExpr{fl, sizeGtep});
m_constraintp->addItemsp(createSizeGteZeroConstraint(fl, sizeVarp));
}
AstVarRef* const sizeVarRefp = new AstVarRef{fl, sizeVarp, VAccess::READ};
sizeVarRefp->user1(true);