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Support complex std::randomize patterns (#6736) (#6737)

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This commit is contained in:
Yilou Wang
2025-12-01 16:26:16 -05:00
committed by GitHub
parent b9b6eb61d9
commit e25c66de07
16 changed files with 273 additions and 198 deletions
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src/V3Randomize.cpp
+84 -33
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@@ -175,6 +175,8 @@ class RandomizeMarkVisitor final : public VNVisitor {
if (varrefp->varp() == varp) return true;
} else if (const AstMemberSel* const memberselp = VN_CAST(exprp, MemberSel)) {
if (memberselp->varp() == varp) return true;
} else if (const AstArraySel* const arrselp = VN_CAST(exprp, ArraySel)) {
if (VN_AS(arrselp->fromp(), VarRef)->varp() == varp) return true;
}
}
return false;
@@ -535,15 +537,20 @@ class RandomizeMarkVisitor final : public VNVisitor {
AstNodeExpr* exprp = argp->exprp();
while (exprp) {
AstVar* randVarp = nullptr;
AstVarRef* varrefp = nullptr;
if (AstMemberSel* const memberSelp = VN_CAST(exprp, MemberSel)) {
randVarp = memberSelp->varp();
exprp = memberSelp->fromp();
} else {
AstVarRef* varrefp = nullptr;
varrefp = VN_AS(exprp, VarRef);
} else if ((varrefp = VN_CAST(exprp, VarRef))) {
randVarp = varrefp->varp();
varrefp->user1(true);
exprp = nullptr;
} else {
varrefp = VN_AS(VN_CAST(exprp, ArraySel)->fromp(), VarRef);
randVarp = varrefp->varp();
varrefp->user1(true);
varrefp->access(VAccess::READWRITE);
exprp = nullptr;
}
UASSERT_OBJ(randVarp, nodep, "No rand variable found");
AstNode* backp = randVarp;
@@ -674,7 +681,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
void visit(AstNodeExpr* nodep) override {
iterateChildrenConst(nodep);
if (!m_constraintExprGenp) return;
if (!m_constraintExprGenp && !m_inStdWith) return;
nodep->user1((nodep->op1p() && nodep->op1p()->user1())
|| (nodep->op2p() && nodep->op2p()->user1())
|| (nodep->op3p() && nodep->op3p()->user1())
@@ -1425,6 +1432,7 @@ class CaptureVisitor final : public VNVisitor {
AstVar* getVar(AstVar* const varp) const {
const auto it = m_varCloneMap.find(varp);
if (it == m_varCloneMap.end()) return nullptr;
if (it->second->isStdRandomizeArg()) return nullptr;
return it->second;
}
@@ -1495,6 +1503,7 @@ class CaptureVisitor final : public VNVisitor {
if (m_ignore.count(nodep)) return;
m_ignore.emplace(nodep);
UASSERT_OBJ(nodep->varp(), nodep, "Variable unlinked");
if (nodep->varp()->isStdRandomizeArg()) return;
CaptureMode capMode = getVarRefCaptureMode(nodep);
if (mode(capMode) == CaptureMode::CAP_NO) return;
if (mode(capMode) == CaptureMode::CAP_VALUE) captureRefByValue(nodep, capMode);
@@ -1633,6 +1642,33 @@ class RandomizeVisitor final : public VNVisitor {
std::set<std::string> m_writtenVars; // Track write_var calls per class to avoid duplicates
// METHODS
// Check if two nodes are semantically equivalent (not pointer equality):
static bool isSimilarNode(const AstNodeExpr* withExpr, const AstNodeExpr* argExpr) {
// VarRef: compare variable pointers
if (VN_IS(argExpr, VarRef) && VN_IS(withExpr, VarRef)) {
return VN_AS(withExpr, VarRef)->varp() == VN_AS(argExpr, VarRef)->varp();
}
// MemberSel: compare object and member (obj.y)
if (VN_IS(argExpr, MemberSel) && VN_IS(withExpr, MemberSel)) {
const AstMemberSel* const withMSp = VN_AS(withExpr, MemberSel);
const AstMemberSel* const argMSp = VN_AS(argExpr, MemberSel);
if (withMSp->varp() != argMSp->varp()) return false;
// Recursively compare the base object expression
return isSimilarNode(withMSp->fromp(), argMSp->fromp());
}
// ArraySel: compare array base and index (arr[i])
if (VN_IS(argExpr, ArraySel) && VN_IS(withExpr, ArraySel)) {
const AstArraySel* const withASp = VN_AS(withExpr, ArraySel);
const AstArraySel* const argASp = VN_AS(argExpr, ArraySel);
// Index must be Sel type, extract VarRef using fromp()
if (!VN_IS(withASp->bitp(), Sel) || !VN_IS(argASp->bitp(), Sel)) return false;
const AstNodeExpr* const withIdxp = VN_AS(withASp->bitp(), Sel)->fromp();
const AstNodeExpr* const argIdxp = VN_AS(argASp->bitp(), Sel)->fromp();
return isSimilarNode(withASp->fromp(), argASp->fromp())
&& isSimilarNode(withIdxp, argIdxp);
}
return false;
}
void createRandomGenerator(AstClass* const classp) {
if (classp->user3p()) return;
if (classp->extendsp()) {
@@ -2605,38 +2641,14 @@ class RandomizeVisitor final : public VNVisitor {
new AstConst{nodep->fileline(), AstConst::WidthedValue{}, 32, 1}});
std::unique_ptr<CaptureVisitor> withCapturep;
int argn = 0;
AstWith* withp = nullptr;
for (AstNode* pinp = nodep->pinsp(); pinp; pinp = pinp->nextp()) {
AstArg* const argp = VN_CAST(pinp, Arg);
AstWith* const withp = VN_CAST(pinp, With);
if (withp) {
FileLine* const fl = nodep->fileline();
withCapturep
= std::make_unique<CaptureVisitor>(withp->exprp(), m_modp, nullptr);
withCapturep->addFunctionArguments(randomizeFuncp);
// Clear old constraints and variables for std::randomize with clause
if (stdrand) {
randomizeFuncp->addStmtsp(
implementConstraintsClearAll(randomizeFuncp->fileline(), stdrand));
}
AstNode* const capturedTreep = withp->exprp()->unlinkFrBackWithNext();
randomizeFuncp->addStmtsp(capturedTreep);
{
ConstraintExprVisitor{m_memberMap, capturedTreep, randomizeFuncp,
stdrand, nullptr, m_writtenVars};
}
AstCExpr* const solverCallp = new AstCExpr{fl};
solverCallp->dtypeSetBit();
solverCallp->add(new AstVarRef{fl, stdrand, VAccess::READWRITE});
solverCallp->add(".next()");
AstVar* const fvarp = VN_AS(randomizeFuncp->fvarp(), Var);
AstVarRef* const retvalReadp = new AstVarRef{fl, fvarp, VAccess::READ};
AstNodeExpr* const andExprp = new AstAnd{fl, retvalReadp, solverCallp};
AstVarRef* const retvalWritep = new AstVarRef{fl, fvarp, VAccess::WRITE};
randomizeFuncp->addStmtsp(new AstAssign{fl, retvalWritep, andExprp});
}
if ((withp = VN_CAST(pinp, With))) break;
}
for (const AstNode* pinp = nodep->pinsp(); pinp; pinp = pinp->nextp()) {
const AstArg* const argp = VN_CAST(pinp, Arg);
if (!argp) continue;
AstNodeExpr* exprp = argp->exprp();
AstCMethodHard* const basicMethodp = new AstCMethodHard{
nodep->fileline(),
new AstVarRef{nodep->fileline(), stdrand, VAccess::READWRITE},
@@ -2644,6 +2656,20 @@ class RandomizeVisitor final : public VNVisitor {
AstVar* const refvarp
= new AstVar{exprp->fileline(), VVarType::MEMBER,
"__Varg"s + std::to_string(++argn), exprp->dtypep()};
refvarp->setStdRandomizeArg();
// Replace argument occurrences in 'with' clause with __Varg* reference.
if (withp) {
withp->foreach([&](AstNodeExpr* exp) {
if (isSimilarNode(exp, exprp)) {
AstVarRef* const replaceVar
= new AstVarRef{exprp->fileline(), refvarp, VAccess::READWRITE};
exp->replaceWith(replaceVar);
replaceVar->user1(exp->user1());
replaceVar->varp()->user2p(m_modp);
VL_DO_DANGLING(pushDeletep(exp), exp);
}
});
}
refvarp->direction(VDirection::REF);
refvarp->funcLocal(true);
refvarp->lifetime(VLifetime::AUTOMATIC_EXPLICIT);
@@ -2666,6 +2692,31 @@ class RandomizeVisitor final : public VNVisitor {
VN_AS(randomizeFuncp->fvarp(), Var), VAccess::READ},
basicMethodp}});
}
if (withp) {
FileLine* const fl = nodep->fileline();
withCapturep = std::make_unique<CaptureVisitor>(withp->exprp(), m_modp, nullptr);
withCapturep->addFunctionArguments(randomizeFuncp);
// Clear old constraints and variables for std::randomize with clause
if (stdrand) {
randomizeFuncp->addStmtsp(
implementConstraintsClearAll(randomizeFuncp->fileline(), stdrand));
}
AstNode* const capturedTreep = withp->exprp()->unlinkFrBackWithNext();
randomizeFuncp->addStmtsp(capturedTreep);
{
ConstraintExprVisitor{m_memberMap, capturedTreep, randomizeFuncp,
stdrand, nullptr, m_writtenVars};
}
AstCExpr* const solverCallp = new AstCExpr{fl};
solverCallp->dtypeSetBit();
solverCallp->add(new AstVarRef{fl, stdrand, VAccess::READWRITE});
solverCallp->add(".next()");
AstVar* const fvarp = VN_AS(randomizeFuncp->fvarp(), Var);
AstNodeExpr* const andExprp
= new AstAnd{fl, new AstVarRef{fl, fvarp, VAccess::READ}, solverCallp};
randomizeFuncp->addStmtsp(
new AstAssign{fl, new AstVarRef{fl, fvarp, VAccess::WRITE}, andExprp});
}
// Remove With nodes from pins as they have been processed
for (AstNode* pinp = nodep->pinsp(); pinp;) {
AstNode* const nextp = pinp->nextp();