Internals: Identify $unit package by netlist pointer

src/V3AstInlines.h

@@ -149,6 +149,8 @@ bool AstActive::hasCombo() const { return m_sentreep->hasCombo(); }
 bool AstActive::hasInitial() const { return m_sentreep->hasInitial(); }
 bool AstActive::hasStatic() const { return m_sentreep->hasStatic(); }
 
+bool AstNodeModule::isDollarUnit() const { return this == v3Global.rootp()->dollarUnitPkgp(); }
+
 AstAlways::AstAlways(AstAssignW* assignp)
     : ASTGEN_SUPER_Always(assignp->fileline(), assignp)
     , m_keyword{VAlwaysKwd::CONT_ASSIGN} {}

src/V3AstNodeOther.h

@@ -358,6 +358,7 @@ public:
     bool maybePointedTo() const override VL_MT_SAFE { return true; }
     string name() const override VL_MT_STABLE { return m_name; }
     virtual bool timescaleMatters() const = 0;
+    inline bool isDollarUnit() const;  // Is the $unit package
     // ACCESSORS
     void name(const string& name) override { m_name = name; }
     string origName() const override { return m_origName; }
@@ -3231,8 +3232,6 @@ public:
     ASTGEN_MEMBERS_AstPackage;
     string verilogKwd() const override { return "package"; }
     bool timescaleMatters() const override { return !isDollarUnit(); }
-    static string dollarUnitName() { return AstNode::encodeName("$unit"); }
-    bool isDollarUnit() const { return name() == dollarUnitName(); }
 };
 class AstPrimitive final : public AstNodeModule {
     // A primitive declaration

src/V3AstNodes.cpp

@@ -1918,7 +1918,7 @@ AstNetlist::AstNetlist()
     : ASTGEN_SUPER_Netlist(new FileLine{FileLine::builtInFilename()})
     , m_typeTablep{new AstTypeTable{fileline()}}
     , m_constPoolp{new AstConstPool{fileline()}}
-    , m_dollarUnitPkgp{new AstPackage{fileline(), AstPackage::dollarUnitName(), "work"}} {
+    , m_dollarUnitPkgp{new AstPackage{fileline(), AstNode::encodeName("$unit"), "work"}} {
     addMiscsp(m_typeTablep);
     addMiscsp(m_constPoolp);
     // packages are always libraries; don't want to make them a "top"

src/V3Dead.cpp

@@ -670,7 +670,7 @@ class DeadVisitor final : public VNVisitor {
                 nextmodp = VN_AS(modp->nextp(), NodeModule);
                 // Keep $unit until m_elimCells stages. Note v3Global.opt.serializeOnly()
                 // won't reach this stage, and will always have an empty $unit. That's ok.
-                const bool keep = !m_elimCells && modp == v3Global.rootp()->dollarUnitPkgp();
+                const bool keep = !m_elimCells && modp->isDollarUnit();
                 if (modp->dead() || (!modp->isTop() && modp->user1() == 0 && !keep)) {
                     // > 2 because L1 is the wrapper, L2 is the top user module
                     UINFO(4, "  Dead module " << modp);
@@ -681,9 +681,7 @@ class DeadVisitor final : public VNVisitor {
                             cellp->modp()->user1Inc(-1);
                         });
                     }
-                    if (modp == v3Global.rootp()->dollarUnitPkgp()) {
-                        v3Global.rootp()->dollarUnitPkgp(nullptr);
-                    }
+                    if (modp->isDollarUnit()) v3Global.rootp()->dollarUnitPkgp(nullptr);
                     deleting(modp);
                     retry = true;
                 }

src/V3LinkCells.cpp

@@ -469,7 +469,7 @@ class LinkCellsVisitor final : public VNVisitor {
             if (nodep->fileline()->filebasenameNoExt() != nodep->prettyName()
                 && !v3Global.opt.isLibraryFile(nodep->fileline()->filename(), nodep->libname())
                 && !VN_IS(nodep, NotFoundModule) && !nodep->recursiveClone()
-                && nodep != v3Global.rootp()->dollarUnitPkgp() && m_modDepth == 1) {
+                && !nodep->isDollarUnit() && m_modDepth == 1) {
                 // We only complain once per file, otherwise library-like files
                 // have a huge mess of warnings
                 const auto itFoundPair = m_declfnWarned.insert(nodep->fileline()->filename());

src/V3LinkDot.cpp

@@ -1220,8 +1220,7 @@ class LinkDotFindVisitor final : public VNVisitor {
         AstNodeModule* const modulesp = nodep->modulesp();
         UASSERT_OBJ(modulesp, nodep, "$unit should always be in the netlist");
         if (!modulesp->nextp()) {
-            UASSERT_OBJ(modulesp == v3Global.rootp()->dollarUnitPkgp(), modulesp,
-                        "Sole module should be $unit");
+            UASSERT_OBJ(modulesp->isDollarUnit(), modulesp, "Sole module should be $unit");
             if (!modulesp->stmtsp()) nodep->v3error("No top level module found");
         }
         for (AstNodeModule* modp = nodep->modulesp(); modp && modp->isTop();