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Support complex expressions as std::randomize arguments (#6860)

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This commit is contained in:
Jakub Wasilewski
2026-01-05 14:37:36 -05:00
committed by GitHub
parent 7023f38d12
commit 72a6da5ac8
4 changed files with 188 additions and 55 deletions
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src/V3Randomize.cpp
+65 -54
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@@ -170,13 +170,23 @@ class RandomizeMarkVisitor final : public VNVisitor {
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;
} else if (const AstArraySel* const arrselp = VN_CAST(exprp, ArraySel)) {
if (VN_AS(arrselp->fromp(), VarRef)->varp() == varp) return true;
const AstNodeExpr* exprp = argp->exprp();
// Traverse through expression to find the base variable
while (exprp) {
if (const AstNodeVarRef* const varrefp = VN_CAST(exprp, NodeVarRef)) {
if (varrefp->varp() == varp) return true;
break;
}
if (const AstMemberSel* const memberselp = VN_CAST(exprp, MemberSel)) {
if (memberselp->varp() == varp) return true;
exprp = memberselp->fromp();
} else if (const AstArraySel* const arrselp = VN_CAST(exprp, ArraySel)) {
exprp = arrselp->fromp();
} else if (const AstStructSel* const strselp = VN_CAST(exprp, StructSel)) {
exprp = strselp->fromp();
} else {
break;
}
}
}
return false;
@@ -331,6 +341,52 @@ class RandomizeMarkVisitor final : public VNVisitor {
}
}
// Get randomized variables from (std::)randomize() arguments
// and mark AstNodeModule nodes in which they are defined
void handleRandomizeArgument(AstNodeExpr* exprp, AstVar* const varp, const bool stdRandomize) {
// IEEE 1800-2023 18.11: "Arguments are limited to the names of properties
// of the calling object; expressions are not allowed."
// However, for compatibility with other simulators, we support complex
// expressions like obj.member[idx].field in inline randomize().
while (exprp) {
AstVar* randVarp = nullptr;
if (AstMemberSel* const memberSelp = VN_CAST(exprp, MemberSel)) {
randVarp = memberSelp->varp();
exprp = memberSelp->fromp();
} else if (AstArraySel* const arraySelp = VN_CAST(exprp, ArraySel)) {
exprp = arraySelp->fromp();
continue; // Skip ArraySel, continue traversing
} else if (AstStructSel* const structSelp = VN_CAST(exprp, StructSel)) {
exprp = structSelp->fromp();
continue; // Skip StructSel, continue traversing
} else if (AstVarRef* const varrefp = VN_CAST(exprp, VarRef)) {
randVarp = varrefp->varp();
varrefp->user1(true);
varrefp->access(VAccess::READWRITE);
exprp = nullptr;
} else {
// All invalid and unsupported expressions should be caught in V3Width
exprp->v3fatalSrc("Unexpected expression type in randomize() argument");
}
UASSERT_OBJ(randVarp, exprp, "No rand variable found");
if (randVarp == varp) return;
AstNode* backp = randVarp;
while (backp && !VN_IS(backp, NodeModule)) backp = backp->backp();
if (stdRandomize) {
UASSERT_OBJ(backp, randVarp, "No class or module found for rand variable");
backp->user1(IS_STD_RANDOMIZED);
} else {
// Inline randomized then
UASSERT_OBJ(VN_IS(backp, Class), randVarp,
"No class found for inline randomized variable");
RandomizeMode randMode = {};
randMode.usesMode = true;
randVarp->user1(randMode.asInt);
backp->user1(IS_RANDOMIZED_INLINE);
}
}
}
// VISITORS
void visit(AstClass* nodep) override {
VL_RESTORER(m_classp);
@@ -534,33 +590,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
for (AstNode* pinp = nodep->pinsp(); pinp; pinp = pinp->nextp()) {
AstArg* const argp = VN_CAST(pinp, Arg);
if (!argp) continue;
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 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;
while (backp && (!VN_IS(backp, Class) && !VN_IS(backp, NodeModule))) {
backp = backp->backp();
}
UASSERT_OBJ(VN_IS(backp, NodeModule), randVarp,
"No class or module found for rand variable");
backp->user1(IS_STD_RANDOMIZED);
}
handleRandomizeArgument(argp->exprp(), nullptr, true);
}
return;
}
@@ -568,7 +598,6 @@ class RandomizeMarkVisitor final : public VNVisitor {
AstArg* const argp = VN_CAST(pinp, Arg);
if (!argp) continue;
classp->user1(IS_RANDOMIZED_INLINE);
AstNodeExpr* exprp = argp->exprp();
AstVar* fromVarp = nullptr; // If nodep is a method call, this is its receiver
if (AstMethodCall* methodCallp = VN_CAST(nodep, MethodCall)) {
if (AstMemberSel* const memberSelp = VN_CAST(methodCallp->fromp(), MemberSel)) {
@@ -578,25 +607,7 @@ class RandomizeMarkVisitor final : public VNVisitor {
fromVarp = varrefp->varp();
}
}
while (exprp) {
AstVar* randVarp = nullptr;
if (AstMemberSel* const memberSelp = VN_CAST(exprp, MemberSel)) {
randVarp = memberSelp->varp();
exprp = memberSelp->fromp();
} else {
AstVarRef* const varrefp = VN_AS(exprp, VarRef);
randVarp = varrefp->varp();
exprp = nullptr;
}
if (randVarp == fromVarp) break;
UASSERT_OBJ(randVarp, nodep, "No rand variable found");
AstNode* backp = randVarp;
while (backp && !VN_IS(backp, Class)) backp = backp->backp();
RandomizeMode randMode = {};
randMode.usesMode = true;
randVarp->user1(randMode.asInt);
VN_AS(backp, Class)->user1(IS_RANDOMIZED_INLINE);
}
handleRandomizeArgument(argp->exprp(), fromVarp, false);
}
}
void visit(AstConstraintExpr* nodep) override {