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Support std::randomize(){...} (#4706) (#6573)

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This commit is contained in:
Yilou Wang
2025-11-14 14:32:01 -05:00
committed by GitHub
parent f32095dd17
commit 048c97f0ae
9 changed files with 179 additions and 50 deletions
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src/V3Randomize.cpp
+101 -12
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@@ -144,12 +144,31 @@ class RandomizeMarkVisitor final : public VNVisitor {
AstNode* m_constraintExprGenp = nullptr; // Current constraint or constraint if expression
AstNodeModule* m_modp; // Current module
AstNodeStmt* m_stmtp = nullptr; // Current statement
AstNodeFTaskRef* m_stdRandCallp = nullptr; // Current std::randomize() call
bool m_inStdWith = false; // True when inside a 'with {}' clause
std::set<AstNodeVarRef*> m_staticRefs; // References to static variables under `with` clauses
AstWith* m_withp = nullptr; // Current 'with' constraint node
std::vector<AstConstraint*> m_clonedConstraints; // List of cloned global constraints
std::unordered_set<const AstVar*> m_processedVars; // Track by variable instance, not class
// METHODS
// Check if a variable is listed in std::randomize() arguments
bool isVarInStdRandomizeArgs(const AstVar* varp) const {
if (!m_inStdWith || !m_stdRandCallp) return false;
for (AstNode* pinp = m_stdRandCallp->pinsp(); pinp; pinp = pinp->nextp()) {
if (VN_IS(pinp, With)) continue;
const AstArg* const argp = VN_CAST(pinp, Arg);
if (!argp) continue;
const AstNodeExpr* const exprp = argp->exprp();
if (const AstNodeVarRef* const varrefp = VN_CAST(exprp, NodeVarRef)) {
if (varrefp->varp() == varp) return true;
} else if (const AstMemberSel* const memberselp = VN_CAST(exprp, MemberSel)) {
if (memberselp->varp() == varp) return true;
}
}
return false;
}
void markMembers(const AstClass* nodep) {
for (const AstClass* classp = nodep; classp;
classp = classp->extendsp() ? classp->extendsp()->classp() : nullptr) {
@@ -353,6 +372,8 @@ class RandomizeMarkVisitor final : public VNVisitor {
if (!nodep->backp()) VL_DO_DANGLING(nodep->deleteTree(), nodep);
}
void visit(AstNodeFTaskRef* nodep) override {
if (nodep->classOrPackagep() && nodep->classOrPackagep()->name() == "std")
m_stdRandCallp = nodep;
iterateChildrenConst(nodep);
if (nodep->name() == "rand_mode") {
AstMethodCall* const methodCallp = VN_CAST(nodep, MethodCall);
@@ -511,6 +532,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
markMembers(classp);
}
if (nodep->classOrPackagep()->name() == "std") {
m_stdRandCallp = nullptr;
for (AstNode* pinp = nodep->pinsp(); pinp; pinp = pinp->nextp()) {
AstArg* const argp = VN_CAST(pinp, Arg);
if (!argp) continue;
@@ -524,6 +546,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
AstVarRef* const varrefp = VN_AS(exprp, VarRef);
randVarp = varrefp->varp();
exprp = nullptr;
varrefp->user1(true);
}
UASSERT_OBJ(randVarp, nodep, "No rand variable found");
AstNode* backp = randVarp;
@@ -591,16 +614,26 @@ class RandomizeMarkVisitor final : public VNVisitor {
if (nodep->varp()->lifetime().isStatic()) m_staticRefs.emplace(nodep);
if (nodep->varp()->rand().isRandomizable()) nodep->user1(true);
// Mark as randomizable if: rand-declared, or listed in std::randomize() args
if (nodep->varp()->rand().isRandomizable() && !(m_inStdWith && m_stdRandCallp)) {
nodep->user1(true);
} else if (isVarInStdRandomizeArgs(nodep->varp())) {
nodep->user1(true);
}
}
void visit(AstMemberSel* nodep) override {
if (!m_constraintExprGenp) return;
iterateChildrenConst(nodep);
// Member select are randomized when both object and member are marked as rand.
// Variable references in with clause are converted to member selects and their from() is
// of type AstLambdaArgRef. They are randomized too.
const bool randObject = nodep->fromp()->user1() || VN_IS(nodep->fromp(), LambdaArgRef);
nodep->user1(randObject && nodep->varp()->rand().isRandomizable());
const bool randMember = nodep->varp()->rand().isRandomizable();
const bool inStdWith = m_inStdWith && m_stdRandCallp;
if (randObject && randMember && !inStdWith) {
nodep->user1(true);
} else if (inStdWith && isVarInStdRandomizeArgs(nodep->varp())) {
nodep->user1(true);
// Mark parent object for constraint expression visitor
if (VN_IS(nodep->fromp(), VarRef)) nodep->fromp()->user1(true);
}
if (m_withp) {
AstNode* backp = m_withp;
@@ -663,7 +696,13 @@ class RandomizeMarkVisitor final : public VNVisitor {
void visit(AstWith* nodep) override {
VL_RESTORER(m_withp);
m_withp = nodep;
for (AstNode* pinp = m_stdRandCallp ? m_stdRandCallp->pinsp() : nullptr; pinp;
pinp = pinp->nextp()) {
AstWith* const withp = VN_CAST(pinp, With);
if (withp == nodep) m_inStdWith = true;
}
iterateChildrenConst(nodep);
m_inStdWith = false;
}
void visit(AstNodeExpr* nodep) override {
@@ -847,8 +886,8 @@ class ConstraintExprVisitor final : public VNVisitor {
AstMemberSel* membersel = nullptr;
std::string smtName;
if (isGlobalConstrained && VN_IS(nodep->backp(), MemberSel)) {
// For global constraints: build complete path from topmost MemberSel
if (VN_IS(nodep->backp(), MemberSel)) {
// Build complete path from topmost MemberSel
AstNode* topMemberSel = nodep->backp();
while (VN_IS(topMemberSel->backp(), MemberSel)) {
topMemberSel = topMemberSel->backp();
@@ -908,8 +947,8 @@ class ConstraintExprVisitor final : public VNVisitor {
dimension = 1;
}
methodp->dtypeSetVoid();
AstClass* const classp
= membersel ? VN_AS(membersel->user2p(), Class) : VN_AS(varp->user2p(), Class);
AstNodeModule* const classp = membersel ? VN_AS(membersel->user2p(), NodeModule)
: VN_AS(varp->user2p(), NodeModule);
if (membersel) {
methodp->addPinsp(membersel);
} else {
@@ -1161,6 +1200,11 @@ class ConstraintExprVisitor final : public VNVisitor {
nodep->replaceWith(varRefp);
VL_DO_DANGLING(pushDeletep(nodep), nodep);
visit(varRefp);
} else if (nodep->user1()) {
iterateChildren(nodep);
nodep->replaceWith(nodep->fromp()->unlinkFrBack());
VL_DO_DANGLING(nodep->deleteTree(), nodep);
return;
} else {
editFormat(nodep);
}
@@ -1356,9 +1400,8 @@ class CaptureVisitor final : public VNVisitor {
newVarp->fileline(fileline);
newVarp->varType(VVarType::BLOCKTEMP);
newVarp->funcLocal(true);
newVarp->direction(VDirection::INPUT);
newVarp->direction(m_targetp ? VDirection::INPUT : VDirection::REF);
newVarp->lifetime(VLifetime::AUTOMATIC_EXPLICIT);
m_varCloneMap.emplace(varrefp->varp(), newVarp);
varp = newVarp;
return true;
@@ -1452,6 +1495,7 @@ class CaptureVisitor final : public VNVisitor {
m_ignore.emplace(thisRefp);
AstMemberSel* const memberSelp
= new AstMemberSel{nodep->fileline(), thisRefp, nodep->varp()};
if (!m_targetp) memberSelp->user1(true);
memberSelp->user2p(m_targetp);
nodep->replaceWith(memberSelp);
VL_DO_DANGLING(pushDeletep(nodep), nodep);
@@ -2051,7 +2095,15 @@ class RandomizeVisitor final : public VNVisitor {
AstCMethodHard* const clearp = new AstCMethodHard{
fileline,
new AstVarRef{fileline, VN_AS(genp->user2p(), NodeModule), genp, VAccess::READWRITE},
VCMethod::RANDOMIZER_CLEAR};
VCMethod::RANDOMIZER_CLEARCONSTRAINTS};
clearp->dtypeSetVoid();
return clearp->makeStmt();
}
AstNodeStmt* implementConstraintsClearAll(FileLine* const fileline, AstVar* const genp) {
AstCMethodHard* const clearp = new AstCMethodHard{
fileline,
new AstVarRef{fileline, VN_AS(genp->user2p(), NodeModule), genp, VAccess::READWRITE},
VCMethod::RANDOMIZER_CLEARALL};
clearp->dtypeSetVoid();
return clearp->makeStmt();
}
@@ -2579,9 +2631,37 @@ class RandomizeVisitor final : public VNVisitor {
new AstVarRef{nodep->fileline(), VN_AS(randomizeFuncp->fvarp(), Var),
VAccess::WRITE},
new AstConst{nodep->fileline(), AstConst::WidthedValue{}, 32, 1}});
std::unique_ptr<CaptureVisitor> withCapturep;
int argn = 0;
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};
}
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 (!argp) continue;
AstNodeExpr* exprp = argp->exprp();
@@ -2614,11 +2694,20 @@ class RandomizeVisitor final : public VNVisitor {
VN_AS(randomizeFuncp->fvarp(), Var), VAccess::READ},
basicMethodp}});
}
// Remove With nodes from pins as they have been processed
for (AstNode* pinp = nodep->pinsp(); pinp;) {
AstNode* const nextp = pinp->nextp();
if (VN_IS(pinp, With)) {
VL_DO_DANGLING(pinp->unlinkFrBack()->deleteTree(), pinp);
}
pinp = nextp;
}
// Replace the node with a call to that function
nodep->name(randomizeFuncp->name());
nodep->taskp(randomizeFuncp);
nodep->dtypeFrom(randomizeFuncp->dtypep());
if (VN_IS(m_modp, Class)) nodep->classOrPackagep(m_modp);
if (withCapturep) nodep->addPinsp(withCapturep->getArgs());
UINFOTREE(9, nodep, "", "std::rnd-call");
UINFOTREE(9, randomizeFuncp, "", "std::rnd-func");
return;