Add `--work` library-selection option (#5891 partial).

Changes

@@ -26,6 +26,7 @@ Verilator 5.037 devel
 * Add BADVLTPRAGMA on unknown Verilator pragmas (#5945). [Shou-Li Hsu]
 * Add ternary operator into branch coverage (#5880). [Ryszard Rozak, Antmicro Ltd.]
 * Add aggregate type error checks (#5570) (#5950). [Shou-Li Hsu]
+* Add `--work` library-selection option (#5891 partial).
 * Add `--filter-type` to verilator_coverage (#6030). [Ryszard Rozak, Antmicro Ltd.]
 * Add `--hierarchical-threads` (#6037). [Bartłomiej Chmiel]
 * Add `MODMISSING` error, in place of unnamed error (#6054). [Paul Swirhun]

bin/verilator

@@ -513,6 +513,7 @@ detailed descriptions of these arguments.
      -Wno-fatal                 Disable fatal exit on warnings
      -Wno-lint                  Disable all lint warnings
      -Wno-style                 Disable all style warnings
+     -work <libname>            Set config library for following files
      -Wpedantic                 Warn on compliance-test issues
      -Wwarn-<message>           Enable specified warning message
      -Wwarn-lint                Enable lint warning message

docs/guide/exe_verilator.rst

@@ -1596,8 +1596,8 @@ Summary:
    When the input Verilog contains more than one top-level module,
    it specifies the name of the module to become the top-level module,
    and sets the default for :vlopt:`--prefix` if not explicitly specified.
-   This is not needed with standard designs with only one top.  See also
+   This is not needed with standard designs with only one top.
-   :option:`MULTITOP` warning.
+   See :ref:`Finding and Binding Modules`.
 
 .. option:: --trace
 
@@ -1881,6 +1881,19 @@ Summary:
    ``-Wno-UNUSEDGENVAR`` ``-Wno-UNUSEDPARAM`` ``-Wno-UNUSEDSIGNAL``
    ``-Wno-VARHIDDEN``.
 
+.. option:: -work <libname>
+
+   Use the specified Verilog config library name for all cells read after
+   this argument.  May be specified multiple times, it will apply to cells
+   read between the given arguments.  E.g. `-work liba a.v -work libb b.v`
+   will use `liba` for modules inside `a.v` or in cells resolved
+   hierarchically under those modules, and will use `libb` for modules
+   inside `b.v` or hierarchically under.
+
+   Defaults to "work" (IEEE 1800-2023 3.3.1).
+
+   See :ref:`Finding and Binding Modules`.
+
 .. option:: -Wpedantic
 
    Warn on any construct demanded by IEEE, and disable all Verilator

docs/guide/languages.rst

@@ -478,7 +478,8 @@ shortreal
   other simulators either do not support float, or convert likewise.
 
 specify specparam
-  All specify blocks and timing checks are ignored.
+  All timing checks and specify blocks (except specparam, which is
+  supported) are ignored.
 
 uwire
   Verilator does not perform warning checking on uwires; it treats the

docs/guide/verilating.rst

@@ -66,6 +66,40 @@ Once a model is built, the next step is typically for the user to run it,
 see :ref:`Simulating`.
 
 
+.. _Finding and Binding Modules:
+
+Finding and Binding Modules
+===========================
+
+Verilator provides several mechanisms to find the source code containing a
+module, primitive, interface, or program ("module" in this section) and
+bind them to an instantiation.  These capabilities are similar to the
+"Precompiling in a single-pass" use model described in IEEE 1800-2023
+33.5.1, although `config` is not yet supported.
+
+Verilator first reads all files provided on the command line and
+:vlopt:`-f` files, and parses all modules within.  Each module is assigned
+to the most recent library specified with :vlopt:`-work`, thus `-work liba
+a.v -work libb b.v` will assign modules in `a.v` to `liba` and modules in
+`b.v` to `libb`.
+
+If a module is not defined from a file on the command-line, Verilator
+attempts to find a filename constructed from the module name using
+:vlopt:`-y` and `+libext`.
+
+Binding begins with the :vlopt:`--top` module, if provided. If not provided
+Verilator attempts to figure out the top module itself, and if multiple
+tops result a :option:`MULTITOP` warning is issued which may be suppressed
+(see details in :option:`MULTITOP`).
+
+Verilator will attempt to bind lower unresolved instances first in the same
+library name as the parent's instantiation library, and if not found search
+globally across all libraries in the order modules were declared.  This
+allows otherwise conflicting duplicate module names between libraries to
+coexist uniquely within each library name.  When IEEE `config use` is
+supported, more complicated selections will be able to be specified.
+
+
 .. _Hierarchical Verilation:
 
 Hierarchical Verilation

docs/spelling.txt

@@ -332,6 +332,7 @@ Prabhat
 Prabhu
 Prateek
 Pre
+Precompiling
 Preprocess
 Pretet
 Pretl

src/V3Ast.cpp

@@ -193,6 +193,11 @@ string AstNode::prettyName(const string& namein) VL_PURE {
                 pos += 7;
                 continue;
             }
+            if (0 == std::strncmp(pos, "__LIB__", 7)) {
+                pretty = "";  // Trim library name before module name
+                pos += 7;
+                continue;
+            }
             if (0 == std::strncmp(pos, "__PVT__", 7)) {
                 pretty += "";
                 pos += 7;

src/V3AstNodeOther.h

@@ -226,6 +226,7 @@ class AstNodeModule VL_NOT_FINAL : public AstNode {
     const string m_origName;  // Name of the module, ignoring name() changes, for dot lookup
     string m_someInstanceName;  // Hierarchical name of some arbitrary instance of this module.
                                 // Used for user messages only.
+    string m_libname;  // Work library
     int m_level = 0;  // 1=top module, 2=cell off top module, ...
     VLifetime m_lifetime;  // Lifetime
     VTimescale m_timeunit;  // Global time unit
@@ -243,10 +244,11 @@ class AstNodeModule VL_NOT_FINAL : public AstNode {
     bool m_recursive : 1;  // Recursive module
     bool m_recursiveClone : 1;  // If recursive, what module it clones, otherwise nullptr
 protected:
-    AstNodeModule(VNType t, FileLine* fl, const string& name)
+    AstNodeModule(VNType t, FileLine* fl, const string& name, const string& libname)
         : AstNode{t, fl}
         , m_name{name}
         , m_origName{name}
+        , m_libname{libname}
         , m_modPublic{false}
         , m_modTrace{false}
         , m_inLibrary{false}
@@ -275,6 +277,8 @@ public:
     void inLibrary(bool flag) { m_inLibrary = flag; }
     void level(int level) { m_level = level; }
     int level() const VL_MT_SAFE { return m_level; }
+    string libname() const { return m_libname; }
+    string prettyLibnameQ() const { return "'" + prettyName(libname()) + "'"; }
     bool isTop() const VL_MT_SAFE { return level() == 1; }
     bool modPublic() const { return m_modPublic; }
     void modPublic(bool flag) { m_modPublic = flag; }
@@ -2507,8 +2511,8 @@ class AstClass final : public AstNodeModule {
     bool m_virtual = false;  // Virtual class
 
 public:
-    AstClass(FileLine* fl, const string& name)
+    AstClass(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_Class(fl, name) {}
+        : ASTGEN_SUPER_Class(fl, name, libname) {}
     ASTGEN_MEMBERS_AstClass;
     string verilogKwd() const override { return "class"; }
     bool maybePointedTo() const override VL_MT_SAFE { return true; }
@@ -2581,8 +2585,8 @@ class AstClassPackage final : public AstNodeModule {
     // @astgen ptr := m_classp : Optional[AstClass]  // Class package this is under
     //                                     // (weak pointer, hard link is other way)
 public:
-    AstClassPackage(FileLine* fl, const string& name)
+    AstClassPackage(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_ClassPackage(fl, name) {}
+        : ASTGEN_SUPER_ClassPackage(fl, name, libname) {}
     ASTGEN_MEMBERS_AstClassPackage;
     string verilogKwd() const override { return "classpackage"; }
     bool timescaleMatters() const override { return false; }
@@ -2592,8 +2596,8 @@ public:
 class AstIface final : public AstNodeModule {
     // A module declaration
 public:
-    AstIface(FileLine* fl, const string& name)
+    AstIface(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_Iface(fl, name) {}
+        : ASTGEN_SUPER_Iface(fl, name, libname) {}
     ASTGEN_MEMBERS_AstIface;
     // Interfaces have `timescale applicability but lots of code seems to
     // get false warnings if we enable this
@@ -2607,13 +2611,13 @@ class AstModule final : public AstNodeModule {
 public:
     class Checker {};  // for constructor type-overload selection
     class Program {};  // for constructor type-overload selection
-    AstModule(FileLine* fl, const string& name)
+    AstModule(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_Module(fl, name) {}
+        : ASTGEN_SUPER_Module(fl, name, libname) {}
-    AstModule(FileLine* fl, const string& name, Checker)
+    AstModule(FileLine* fl, const string& name, const string& libname, Checker)
-        : ASTGEN_SUPER_Module(fl, name)
+        : ASTGEN_SUPER_Module(fl, name, libname)
         , m_isChecker{true} {}
-    AstModule(FileLine* fl, const string& name, Program)
+    AstModule(FileLine* fl, const string& name, const string& libname, Program)
-        : ASTGEN_SUPER_Module(fl, name)
+        : ASTGEN_SUPER_Module(fl, name, libname)
         , m_isProgram{true} {}
     ASTGEN_MEMBERS_AstModule;
     string verilogKwd() const override {
@@ -2628,8 +2632,8 @@ public:
 class AstNotFoundModule final : public AstNodeModule {
     // A missing module declaration
 public:
-    AstNotFoundModule(FileLine* fl, const string& name)
+    AstNotFoundModule(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_NotFoundModule(fl, name) {}
+        : ASTGEN_SUPER_NotFoundModule(fl, name, libname) {}
     ASTGEN_MEMBERS_AstNotFoundModule;
     string verilogKwd() const override { return "/*not-found-*/ module"; }
     bool timescaleMatters() const override { return false; }
@@ -2637,8 +2641,8 @@ public:
 class AstPackage final : public AstNodeModule {
     // A package declaration
 public:
-    AstPackage(FileLine* fl, const string& name)
+    AstPackage(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_Package(fl, name) {}
+        : ASTGEN_SUPER_Package(fl, name, libname) {}
     ASTGEN_MEMBERS_AstPackage;
     string verilogKwd() const override { return "package"; }
     bool timescaleMatters() const override { return !isDollarUnit(); }
@@ -2648,8 +2652,8 @@ public:
 class AstPrimitive final : public AstNodeModule {
     // A primitive declaration
 public:
-    AstPrimitive(FileLine* fl, const string& name)
+    AstPrimitive(FileLine* fl, const string& name, const string& libname)
-        : ASTGEN_SUPER_Primitive(fl, name) {}
+        : ASTGEN_SUPER_Primitive(fl, name, libname) {}
     ASTGEN_MEMBERS_AstPrimitive;
     string verilogKwd() const override { return "primitive"; }
     bool timescaleMatters() const override { return false; }

src/V3AstNodes.cpp

@@ -1353,7 +1353,7 @@ AstBasicDType* AstTypeTable::findInsertSameDType(AstBasicDType* nodep) {
 
 AstConstPool::AstConstPool(FileLine* fl)
     : ASTGEN_SUPER_ConstPool(fl)
-    , m_modp{new AstModule{fl, "@CONST-POOL@"}}
+    , m_modp{new AstModule{fl, "@CONST-POOL@", "work"}}
     , m_scopep{new AstScope{fl, m_modp, "@CONST-POOL@", nullptr, nullptr}} {
     this->modulep(m_modp);
     m_modp->addStmtsp(m_scopep);
@@ -2298,7 +2298,7 @@ void AstNetlist::dumpJson(std::ostream& str) const {
 }
 AstPackage* AstNetlist::dollarUnitPkgAddp() {
     if (!m_dollarUnitPkgp) {
-        m_dollarUnitPkgp = new AstPackage{fileline(), AstPackage::dollarUnitName()};
+        m_dollarUnitPkgp = new AstPackage{fileline(), AstPackage::dollarUnitName(), "work"};
         // packages are always libraries; don't want to make them a "top"
         m_dollarUnitPkgp->inLibrary(true);
         m_dollarUnitPkgp->modTrace(false);  // may reconsider later
@@ -2325,6 +2325,7 @@ void AstNodeModule::dump(std::ostream& str) const {
         str << " [RECURSIVE]";
     }
     str << " [" << timeunit() << "]";
+    if (libname() != "work") str << " libname=" << libname();
 }
 void AstNodeModule::dumpJson(std::ostream& str) const {
     dumpJsonStrFunc(str, origName);
@@ -2335,6 +2336,7 @@ void AstNodeModule::dumpJson(std::ostream& str) const {
     dumpJsonBoolFunc(str, recursiveClone);
     dumpJsonBoolFunc(str, recursive);
     dumpJsonStr(str, "timeunit", timeunit().ascii());
+    if (libname() != "work") dumpJsonStr(str, "libname=", libname());
     dumpJsonGen(str);
 }
 void AstPackageExport::dump(std::ostream& str) const {

src/V3Class.cpp

@@ -93,7 +93,7 @@ class ClassVisitor final : public VNVisitor {
         // Make containing package
         // Note origName is the same as the class origName so errors look correct
         AstClassPackage* const packagep
-            = new AstClassPackage{nodep->fileline(), nodep->origName()};
+            = new AstClassPackage{nodep->fileline(), nodep->origName(), nodep->libname()};
         packagep->name(nodep->name() + "__Vclpkg");
         nodep->editCountInc();
         nodep->classOrPackagep(packagep);
@@ -138,6 +138,7 @@ class ClassVisitor final : public VNVisitor {
     }
     void visit(AstNodeModule* nodep) override {
         // Visit for NodeModules that are not AstClass (AstClass is-a AstNodeModule)
+        // Classes are always under a Package (perhaps $unit) or a module
         VL_RESTORER(m_prefix);
         VL_RESTORER(m_modp);
         m_modp = nodep;

src/V3EmitCMake.cpp

@@ -39,11 +39,21 @@ class CMakeEmitter final {
     template <typename T_List>
     static string cmake_list(const T_List& strs) {
         string s;
-        for (auto it = strs.begin(); it != strs.end(); ++it) {
+        for (auto& itr : strs) {
+            if (!s.empty()) s += ' ';
             s += '"';
-            s += V3OutFormatter::quoteNameControls(*it);
+            s += V3OutFormatter::quoteNameControls(itr);
+            s += '"';
+        }
+        return s;
+    }
+    static string cmake_list(const VFileLibList& strs) {
+        string s;
+        for (auto& itr : strs) {
+            if (!s.empty()) s += ' ';
+            s += '"';
+            s += V3OutFormatter::quoteNameControls(itr.filename());
             s += '"';
-            if (it != strs.end()) s += ' ';
         }
         return s;
     }
@@ -193,8 +203,8 @@ class CMakeEmitter final {
                 *of << " ";
                 const string vFile = hblockp->vFileIfNecessary();
                 if (!vFile.empty()) *of << vFile << " ";
-                const V3StringList& vFiles = v3Global.opt.vFiles();
+                for (const auto& i : v3Global.opt.vFiles())
-                for (const string& i : vFiles) *of << V3Os::filenameRealPath(i) << " ";
+                    *of << V3Os::filenameRealPath(i.filename()) << " ";
                 *of << " VERILATOR_ARGS ";
                 *of << "-f " << hblockp->commandArgsFilename(true)
                     << " -CFLAGS -fPIC"  // hierarchical block will be static, but may be linked

src/V3EmitMk.cpp

@@ -814,13 +814,12 @@ class EmitMkHierVerilation final {
         const string verilator_wrapper = V3Os::filenameDir(fullpath_bin) + "/verilator";
         of.puts("VM_HIER_VERILATOR := " + verilator_wrapper + "\n");
         of.puts("VM_HIER_INPUT_FILES := \\\n");
-        const V3StringList& vFiles = v3Global.opt.vFiles();
+        for (const auto& i : v3Global.opt.vFiles())
-        for (const string& i : vFiles) of.puts("  " + V3Os::filenameRealPath(i) + " \\\n");
+            of.puts("  " + V3Os::filenameRealPath(i.filename()) + " \\\n");
         of.puts("\n");
-        const V3StringSet& libraryFiles = v3Global.opt.libraryFiles();
         of.puts("VM_HIER_VERILOG_LIBS := \\\n");
-        for (const string& i : libraryFiles) {
+        for (const auto& i : v3Global.opt.libraryFiles()) {
-            of.puts("  " + V3Os::filenameRealPath(i) + " \\\n");
+            of.puts("  " + V3Os::filenameRealPath(i.filename()) + " \\\n");
         }
         of.puts("\n");
     }

src/V3EmitMkJson.cpp

@@ -133,9 +133,9 @@ class V3EmitMkJsonEmitter final {
                 const string vFile = hblockp->vFileIfNecessary();
                 if (!vFile.empty()) sources.emplace_back(vFile);
 
-                const V3StringList& vFiles = v3Global.opt.vFiles();
+                for (const auto& i : v3Global.opt.vFiles())
-                for (const string& i : vFiles)
+                    sources.emplace_back(
-                    sources.emplace_back(V3Os::filenameSlashPath(V3Os::filenameRealPath(i)));
+                        V3Os::filenameSlashPath(V3Os::filenameRealPath(i.filename())));
 
                 std::vector<std::string> cflags;
                 cflags.emplace_back("-fPIC");
@@ -156,9 +156,9 @@ class V3EmitMkJsonEmitter final {
             for (const auto& itr : *planp)
                 sources.emplace_back(makeDir + "/" + itr.second->hierWrapperFilename(true));
 
-            const V3StringList& vFiles = v3Global.opt.vFiles();
+            for (const auto& itr : v3Global.opt.vFiles())
-            for (const string& i : vFiles)
+                sources.emplace_back(
-                sources.emplace_back(V3Os::filenameSlashPath(V3Os::filenameRealPath(i)));
+                    V3Os::filenameSlashPath(V3Os::filenameRealPath(itr.filename())));
 
             of.begin()
                 .put("prefix", v3Global.opt.prefix())

src/V3Fork.cpp

@@ -81,7 +81,8 @@ public:
     ForkDynScopeInstance& createInstancePrototype() {
         UASSERT_OBJ(!m_instance.initialized(), m_procp, "Dynamic scope already instantiated.");
 
-        m_instance.m_classp = new AstClass{m_procp->fileline(), generateDynScopeClassName()};
+        m_instance.m_classp
+            = new AstClass{m_procp->fileline(), generateDynScopeClassName(), m_modp->libname()};
         UINFO(9, "new dynscope class " << m_instance.m_classp);
         m_instance.m_refDTypep
             = new AstClassRefDType{m_procp->fileline(), m_instance.m_classp, nullptr};

src/V3Global.cpp

@@ -60,42 +60,39 @@ void V3Global::readFiles() {
     if (v3Global.opt.stdWaiver()) {
         parser.parseFile(
             new FileLine{V3Options::getStdWaiverPath()}, V3Options::getStdWaiverPath(), false,
-            "Cannot find verilated_std_waiver.vlt containing built-in lint waivers: ");
+            "work", "Cannot find verilated_std_waiver.vlt containing built-in lint waivers: ");
     }
     // Read .vlt files
-    const V3StringSet& vltFiles = v3Global.opt.vltFiles();
+    for (auto& filelib : v3Global.opt.vltFiles()) {
-    for (const string& filename : vltFiles) {
+        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filelib.filename(), false,
-        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filename, false,
+                         filelib.libname(), "Cannot find file containing .vlt file: ");
-                         "Cannot find file containing .vlt file: ");
     }
 
     // Parse the std package
     if (v3Global.opt.stdPackage()) {
         parser.parseFile(new FileLine{V3Options::getStdPackagePath()},
-                         V3Options::getStdPackagePath(), false,
+                         V3Options::getStdPackagePath(), false, "work",
                          "Cannot find verilated_std.sv containing built-in std:: definitions: ");
     }
 
     // Read top module
-    const V3StringList& vFiles = v3Global.opt.vFiles();
+    for (const auto& filelib : v3Global.opt.vFiles()) {
-    for (const string& filename : vFiles) {
+        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filelib.filename(), false,
-        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filename, false,
+                         filelib.libname(), "Cannot find file containing module: ");
-                         "Cannot find file containing module: ");
     }
 
     // Read libraries
     // To be compatible with other simulators,
     // this needs to be done after the top file is read
-    const V3StringSet& libraryFiles = v3Global.opt.libraryFiles();
+    for (const auto& filelib : v3Global.opt.libraryFiles()) {
-    for (const string& filename : libraryFiles) {
+        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filelib.filename(), true,
-        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filename, true,
+                         filelib.libname(), "Cannot find file containing library module: ");
-                         "Cannot find file containing library module: ");
     }
 
     // Read hierarchical type parameter file
-    const string filename = v3Global.opt.hierParamFile();
+    for (const auto& filelib : v3Global.opt.hierParamFile()) {
-    if (!filename.empty()) {
+        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filelib.filename(), false,
-        parser.parseFile(new FileLine{FileLine::commandLineFilename()}, filename, false,
+                         filelib.libname(),
                          "Cannot open file containing hierarchical parameter declarations: ");
     }
 

src/V3HierBlock.cpp

@@ -116,12 +116,11 @@ static void V3HierWriteCommonInputs(const V3HierBlock* hblockp, std::ostream* of
     if (hblockp) topModuleFile = hblockp->vFileIfNecessary();
     if (!forCMake) {
         if (!topModuleFile.empty()) *of << topModuleFile << "\n";
-        const V3StringList& vFiles = v3Global.opt.vFiles();
+        for (const auto& i : v3Global.opt.vFiles()) *of << i.filename() << "\n";
-        for (const string& i : vFiles) *of << i << "\n";
     }
-    const V3StringSet& libraryFiles = v3Global.opt.libraryFiles();
+    for (const auto& i : v3Global.opt.libraryFiles()) {
-    for (const string& i : libraryFiles) {
+        if (V3Os::filenameRealPath(i.filename()) != topModuleFile)
-        if (V3Os::filenameRealPath(i) != topModuleFile) *of << "-v " << i << "\n";
+            *of << "-v " << i.filename() << "\n";
     }
 }
 
@@ -251,9 +250,9 @@ string V3HierBlock::hierGeneratedFilenames(bool withDir) const {
 
 string V3HierBlock::vFileIfNecessary() const {
     string filename = V3Os::filenameRealPath(m_modp->fileline()->filename());
-    for (const string& v : v3Global.opt.vFiles()) {
+    for (const auto& v : v3Global.opt.vFiles()) {
         // Already listed in vFiles, so no need to add the file.
-        if (filename == V3Os::filenameRealPath(v)) return "";
+        if (filename == V3Os::filenameRealPath(v.filename())) return "";
     }
     return filename;
 }

src/V3LinkCells.cpp

@@ -127,14 +127,34 @@ class LinkCellsVisitor final : public VNVisitor {
         const V3GraphEdge* const edgep = new V3GraphEdge{&m_graph, fromp, top, weight, cuttable};
         UINFO(9, "    newEdge " << edgep << " " << fromp->name() << " -> " << top->name());
     }
-
+    void insertModInLib(const string& name, const string& libname, AstNodeModule* nodep) {
-    AstNodeModule* findModuleSym(const string& modName) {
+        // Be able to find the module under it's library using the name it was given
-        const VSymEnt* const foundp = m_mods.rootp()->findIdFallback(modName);
+        VSymEnt* libSymp = m_mods.rootp()->findIdFlat(libname);
-        return foundp ? VN_AS(foundp->nodep(), NodeModule) : nullptr;
+        if (!libSymp)
+            libSymp = m_mods.rootp()->insert(libname, new VSymEnt{&m_mods, v3Global.rootp()});
+        libSymp->insert(name, new VSymEnt{&m_mods, nodep});
     }
 
-    AstNodeModule* resolveModule(AstNode* nodep, const string& modName) {
+    AstNodeModule* findModuleLibSym(const string& modName, const string& libname) {
-        AstNodeModule* modp = findModuleSym(modName);
+        // Given module name and library name, find within that exact library
+        const VSymEnt* const libSymp = m_mods.rootp()->findIdFallback(libname);
+        if (!libSymp) return nullptr;
+        const VSymEnt* const foundp = libSymp->findIdFallback(modName);
+        return foundp ? VN_AS(foundp->nodep(), NodeModule) : nullptr;
+    }
+    AstNodeModule* findModuleSym(const string& modName, const string& libname) {
+        // Given module and library to start search in, resolve using config library choices
+        // TODO support IEEE config library search order
+        // First search local library
+        AstNodeModule* foundp = findModuleLibSym(modName, libname);
+        if (foundp) return foundp;
+        // THen search global
+        foundp = findModuleLibSym(modName, "__GLOBAL");
+        return foundp;
+    }
+
+    AstNodeModule* resolveModule(AstNode* nodep, const string& modName, const string& libname) {
+        AstNodeModule* modp = findModuleSym(modName, libname);
         if (!modp) {
             // Read-subfile
             // If file not found, make AstNotFoundModule, rather than error out.
@@ -142,12 +162,12 @@ class LinkCellsVisitor final : public VNVisitor {
             const string prettyName = AstNode::prettyName(modName);
             V3Parse parser{v3Global.rootp(), m_filterp};
             // true below -> other simulators treat modules in link-found files as library cells
-            parser.parseFile(nodep->fileline(), prettyName, true, "");
+            parser.parseFile(nodep->fileline(), prettyName, true, m_modp->libname(), "");
             V3Error::abortIfErrors();
             // We've read new modules, grab new pointers to their names
             readModNames();
             // Check again
-            modp = findModuleSym(modName);
+            modp = findModuleSym(modName, libname);
             if (!modp) {
                 // This shouldn't throw a message as parseFile will create
                 // a AstNotFoundModule for us
@@ -188,7 +208,7 @@ class LinkCellsVisitor final : public VNVisitor {
             m_modp = nodep;
             UINFO(4, "Link Module: " << nodep);
             if (nodep->fileline()->filebasenameNoExt() != nodep->prettyName()
-                && !v3Global.opt.isLibraryFile(nodep->fileline()->filename())
+                && !v3Global.opt.isLibraryFile(nodep->fileline()->filename(), nodep->libname())
                 && !VN_IS(nodep, NotFoundModule) && !nodep->recursiveClone()
                 && !nodep->internal()) {
                 // We only complain once per file, otherwise library-like files
@@ -228,7 +248,7 @@ class LinkCellsVisitor final : public VNVisitor {
         UINFO(4, "Link IfaceRef: " << nodep);
         // Use findIdUpward instead of findIdFlat; it doesn't matter for now
         // but we might support modules-under-modules someday.
-        AstNodeModule* const modp = resolveModule(nodep, nodep->ifaceName());
+        AstNodeModule* const modp = resolveModule(nodep, nodep->ifaceName(), m_modp->libname());
         if (modp) {
             if (VN_IS(modp, Iface)) {
                 // Track module depths, so can sort list from parent down to children
@@ -259,7 +279,7 @@ class LinkCellsVisitor final : public VNVisitor {
         // Package Import: We need to do the package before the use of a package
         iterateChildren(nodep);
         if (!nodep->packagep()) {
-            AstNodeModule* const modp = resolveModule(nodep, nodep->pkgName());
+            AstNodeModule* const modp = resolveModule(nodep, nodep->pkgName(), m_modp->libname());
             if (AstPackage* const pkgp = VN_CAST(modp, Package)) nodep->packagep(pkgp);
             if (!nodep->packagep()) {
                 nodep->v3error("Export package not found: " << nodep->prettyPkgNameQ());
@@ -271,7 +291,7 @@ class LinkCellsVisitor final : public VNVisitor {
         // Package Import: We need to do the package before the use of a package
         iterateChildren(nodep);
         if (!nodep->packagep()) {
-            AstNodeModule* const modp = resolveModule(nodep, nodep->pkgName());
+            AstNodeModule* const modp = resolveModule(nodep, nodep->pkgName(), m_modp->libname());
             if (AstPackage* const pkgp = VN_CAST(modp, Package)) nodep->packagep(pkgp);
             // If not found, V3LinkDot will report errors
             if (!nodep->packagep()) {
@@ -289,7 +309,7 @@ class LinkCellsVisitor final : public VNVisitor {
         // this move to post param, which would mean we do not auto-read modules
         // and means we cannot compute module levels until later.
         UINFO(4, "Link Bind: " << nodep);
-        AstNodeModule* const modp = resolveModule(nodep, nodep->name());
+        AstNodeModule* const modp = resolveModule(nodep, nodep->name(), m_modp->libname());
         if (modp) {
             AstNode* const cellsp = nodep->cellsp()->unlinkFrBackWithNext();
             // Module may have already linked, so need to pick up these new cells
@@ -325,7 +345,7 @@ class LinkCellsVisitor final : public VNVisitor {
             UINFO(4, "Link Cell: " << nodep);
             // Use findIdFallback instead of findIdFlat; it doesn't matter for now
             // but we might support modules-under-modules someday.
-            AstNodeModule* cellmodp = resolveModule(nodep, nodep->modName());
+            AstNodeModule* cellmodp = resolveModule(nodep, nodep->modName(), m_modp->libname());
             if (cellmodp) {
                 if (cellmodp == m_modp || cellmodp->user2p() == m_modp) {
                     UINFO(1, "Self-recursive module " << cellmodp);
@@ -529,7 +549,7 @@ class LinkCellsVisitor final : public VNVisitor {
             if (pinp->name() == "") pinp->name("__paramNumber" + cvtToStr(pinp->pinNum()));
         }
         if (m_varp) {  // Parser didn't know what was interface, resolve now
-            AstNodeModule* const varModp = findModuleSym(nodep->name());
+            AstNodeModule* const varModp = findModuleSym(nodep->name(), m_modp->libname());
             if (AstIface* const ifacep = VN_CAST(varModp, Iface)) {
                 // Might be an interface, but might also not really be due to interface being
                 // hidden by another declaration.  Assume it is relevant and order as-if.
@@ -591,21 +611,26 @@ class LinkCellsVisitor final : public VNVisitor {
         // Look at all modules, and store pointers to all module names
         for (AstNodeModule *nextp, *nodep = v3Global.rootp()->modulesp(); nodep; nodep = nextp) {
             nextp = VN_AS(nodep->nextp(), NodeModule);
-            if (v3Global.opt.hierChild() && nodep->name() == hierIt->second.origName()) {
+            if (v3Global.opt.hierChild() && nodep->origName() == hierIt->second.origName()) {
                 nodep->name(hierIt->first);  // Change name of this module to be mangled name
                                              // considering parameter
             }
-            const AstNodeModule* const foundp = findModuleSym(nodep->name());
+            const AstNodeModule* const libFoundp = findModuleLibSym(nodep->origName(), nodep->libname());
-            if (foundp && foundp != nodep) {
+            const AstNodeModule* const globalFoundp = findModuleLibSym(nodep->name(), "__GLOBAL");
-                if (!(foundp->fileline()->warnIsOff(V3ErrorCode::MODDUP)
+            if (libFoundp && libFoundp == nodep) {
+                // Ok
+            } else if (libFoundp && !globalFoundp) {
+                nodep->v3fatalSrc("Module should be found globally if inserted in lib");
+            } else if (libFoundp) {
+                if (!(libFoundp->fileline()->warnIsOff(V3ErrorCode::MODDUP)
                       || nodep->fileline()->warnIsOff(V3ErrorCode::MODDUP)
                       || hierBlocks.find(nodep->name()) != hierBlocks.end())) {
                     nodep->v3warn(MODDUP, "Duplicate declaration of module: "
                                               << nodep->prettyNameQ() << '\n'
                                               << nodep->warnContextPrimary() << '\n'
-                                              << foundp->warnOther()
+                                              << libFoundp->warnOther()
                                               << "... Location of original declaration\n"
-                                              << foundp->warnContextSecondary());
+                                              << libFoundp->warnContextSecondary());
                 }
                 if (VN_IS(nodep, Package)) {
                     // Packages may be imported, we instead rename to be unique
@@ -614,8 +639,16 @@ class LinkCellsVisitor final : public VNVisitor {
                     nodep->unlinkFrBack();
                     VL_DO_DANGLING(pushDeletep(nodep), nodep);
                 }
-            } else if (!foundp) {
+            } else if (!libFoundp && globalFoundp && globalFoundp != nodep) {
-                m_mods.rootp()->insert(nodep->name(), new VSymEnt{&m_mods, nodep});
+                // ...__LIB__ stripped by prettyName
+                const string newName = nodep->libname() + "__LIB__" + nodep->origName();
+                UINFO(9, "Module rename as in multiple libraries " << newName << " <- " << nodep);
+                insertModInLib(nodep->origName(), nodep->libname(), nodep);  // Original name
+                nodep->name(newName);
+                insertModInLib(nodep->name(), "__GLOBAL", nodep);
+            } else if (!libFoundp) {
+                insertModInLib(nodep->origName(), nodep->libname(), nodep);
+                insertModInLib(nodep->name(), "__GLOBAL", nodep);
             }
         }
         // if (debug() >= 9) m_mods.dump(cout, "-syms: ");
@@ -641,7 +674,9 @@ public:
         iterate(nodep);
     }
     ~LinkCellsVisitor() override {
-        if (debug() >= 5 || dumpGraphLevel() >= 5) { m_mods.dumpFilePrefixed("linkcells"); }
+        if (debug() >= 5 || dumpGraphLevel() >= 5) {
+            m_mods.dumpFilePrefixed("linkcells");
+        }
     }
 };
 

src/V3LinkLevel.cpp

@@ -164,7 +164,7 @@ void V3LinkLevel::wrapTop(AstNetlist* rootp) {
         return;
     }
 
-    AstNodeModule* const newmodp = new AstModule{oldmodp->fileline(), "$root"};
+    AstNodeModule* const newmodp = new AstModule{oldmodp->fileline(), "$root", oldmodp->libname()};
     newmodp->name(AstNode::encodeName(newmodp->name()));  // so origName is nice
     // Make the new module first in the list
     oldmodp->unlinkFrBackWithNext();

src/V3LinkResolve.cpp

@@ -313,7 +313,8 @@ class LinkResolveVisitor final : public VNVisitor {
                         nodep->v3warn(E_UNSUPPORTED, "Unsupported: %l in $fscanf");
                         fmt = "";
                     }
-                    if (m_modp) fmt = VString::quotePercent(m_modp->prettyName());
+                    if (m_modp)
+                        fmt = AstNode::prettyName(m_modp->libname()) + "." + m_modp->prettyName();
                     break;
                 default:  // Most operators, just move to next argument
                     if (!V3Number::displayedFmtLegal(ch, isScan)) {

src/V3Options.cpp

@@ -380,10 +380,12 @@ bool V3Options::isFuture0(const string& flag) const {
 bool V3Options::isFuture1(const string& flag) const {
     return m_future1s.find(flag) != m_future1s.end();
 }
-bool V3Options::isLibraryFile(const string& filename) const {
+bool V3Options::isLibraryFile(const string& filename, const string& libname) const {
-    return m_libraryFiles.find(filename) != m_libraryFiles.end();
+    return m_libraryFiles.find({filename, libname}) != m_libraryFiles.end();
+}
+void V3Options::addLibraryFile(const string& filename, const string& libname) {
+    m_libraryFiles.insert({filename, libname});
 }
-void V3Options::addLibraryFile(const string& filename) { m_libraryFiles.insert(filename); }
 bool V3Options::isClocker(const string& signame) const {
     return m_clockers.find(signame) != m_clockers.end();
 }
@@ -392,12 +394,14 @@ bool V3Options::isNoClocker(const string& signame) const {
     return m_noClockers.find(signame) != m_noClockers.end();
 }
 void V3Options::addNoClocker(const string& signame) { m_noClockers.insert(signame); }
-void V3Options::addVFile(const string& filename) {
+void V3Options::addVFile(const string& filename, const string& libname) {
     // We use a list for v files, because it's legal to have includes
     // in a specific order and multiple of them.
-    m_vFiles.push_back(filename);
+    m_vFiles.push_back({filename, libname});
+}
+void V3Options::addVltFile(const string& filename, const string& libname) {
+    m_vltFiles.insert({filename, libname});
 }
-void V3Options::addVltFile(const string& filename) { m_vltFiles.insert(filename); }
 void V3Options::addForceInc(const string& filename) { m_forceIncs.push_back(filename); }
 
 void V3Options::addLineArg(const string& arg) { m_impp->m_lineArgs.push_back(arg); }
@@ -416,7 +420,7 @@ string V3Options::allArgsString() const VL_MT_SAFE {
 // Delete some options for Verilation of the hierarchical blocks.
 string V3Options::allArgsStringForHierBlock(bool forTop) const {
     std::set<string> vFiles;
-    for (const auto& vFile : m_vFiles) vFiles.insert(vFile);
+    for (const auto& vFile : m_vFiles) vFiles.insert(vFile.filename());
     string out;
     bool stripArg = false;
     bool stripArgIfNum = false;
@@ -1058,16 +1062,16 @@ void V3Options::parseOpts(FileLine* fl, int argc, char** argv) VL_MT_DISABLED {
 
     // Default certain options and error check
     // Detailed error, since this is what we often get when run with minimal arguments
-    const V3StringList& vFilesList = vFiles();
+    if (vFiles().empty()) {
-    if (vFilesList.empty()) {
         v3fatal("verilator: No Input Verilog file specified on command line, "
                 "see verilator --help for more information\n");
     }
 
     // Default prefix to the filename
     if (prefix() == "" && topModule() != "") m_prefix = "V"s + AstNode::encodeName(topModule());
-    if (prefix() == "" && vFilesList.size() >= 1)
+    if (prefix() == "" && vFiles().size() >= 1)
-        m_prefix = "V"s + AstNode::encodeName(V3Os::filenameNonDirExt(*(vFilesList.begin())));
+        m_prefix
+            = "V"s + AstNode::encodeName(V3Os::filenameNonDirExt(vFiles().begin()->filename()));
     if (modPrefix() == "") m_modPrefix = prefix();
 
     // Find files in makedir
@@ -1386,8 +1390,9 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
         m_hierBlocks.emplace(opt.mangledName(), opt);
     });
     DECL_OPTION("-hierarchical-child", Set, &m_hierChild);
-    DECL_OPTION("-hierarchical-params-file", CbVal,
+    DECL_OPTION("-hierarchical-params-file", CbVal, [this](const char* optp) {
-                [this](const char* optp) { m_hierParamsFile = optp; });
+        m_hierParamsFile.push_back({optp, work()});
+    });
 
     DECL_OPTION("-I", CbPartialMatch,
                 [this, &optdir](const char* optp) { addIncDirUser(parseFileArg(optdir, optp)); });
@@ -1699,7 +1704,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
         std::exit(0);
     });
     DECL_OPTION("-v", CbVal, [this, &optdir](const char* valp) {
-        V3Options::addLibraryFile(parseFileArg(optdir, valp));
+        V3Options::addLibraryFile(parseFileArg(optdir, valp), work());
     });
     DECL_OPTION("-valgrind", CbCall, []() {});  // Processed only in bin/verilator shell
     DECL_OPTION("-verilate", OnOff, &m_verilate);
@@ -1762,6 +1767,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
     DECL_OPTION("-Wno-style", CbCall, []() { FileLine::globalWarnStyleOff(true); });
     DECL_OPTION("-Wno-UNUSED", CbCall, []() { FileLine::globalWarnUnusedOff(true); });
     DECL_OPTION("-Wno-WIDTH", CbCall, []() { FileLine::globalWarnOff(V3ErrorCode::WIDTH, true); });
+    DECL_OPTION("-work", Set, &m_work);
     DECL_OPTION("-Wpedantic", CbCall, [this]() {
         m_pedantic = true;
         V3Error::pretendError(V3ErrorCode::ASSIGNIN, false);
@@ -1888,9 +1894,9 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc,
                        || suffixed(filename, ".so")) {
                 V3Options::addLdLibs(filename);
             } else if (suffixed(filename, ".vlt")) {
-                V3Options::addVltFile(filename);
+                V3Options::addVltFile(filename, work());
             } else {
-                V3Options::addVFile(filename);
+                V3Options::addVFile(filename, work());
             }
             ++i;
         }

src/V3Options.h

@@ -59,6 +59,34 @@ constexpr bool operator==(const VOptionBool& lhs, const VOptionBool& rhs) {
 constexpr bool operator==(const VOptionBool& lhs, VOptionBool::en rhs) { return lhs.m_e == rhs; }
 constexpr bool operator==(VOptionBool::en lhs, const VOptionBool& rhs) { return lhs == rhs.m_e; }
 
+//######################################################################
+
+class VFileLibName final {
+    // Filename and libname pair
+    const string m_filename;  // Filename
+    const string m_libname;  // Libname
+public:
+    VFileLibName(const string& filename, const string& libname)
+        : m_filename{filename}
+        , m_libname{libname} {}
+    VFileLibName(const VFileLibName& rhs)
+        : m_filename{rhs.m_filename}
+        , m_libname{rhs.m_libname} {}
+    string filename() const { return m_filename; }
+    string libname() const { return m_libname; }
+    bool operator==(const VFileLibName& rhs) const {
+        return m_filename == rhs.m_filename && m_libname == rhs.m_libname;
+    }
+    bool operator<(const VFileLibName& rhs) const {
+        if (m_filename < rhs.m_filename) return true;
+        if (m_filename > rhs.m_filename) return false;
+        return m_libname < rhs.m_libname;
+    }
+};
+
+using VFileLibList = std::vector<VFileLibName>;
+using VFileLibSet = std::set<VFileLibName>;
+
 // ######################################################################
 
 class VTimescale final {
@@ -207,11 +235,11 @@ private:
     V3StringSet m_futures;      // argument: -Wfuture- list
     V3StringSet m_future0s;     // argument: -future list
     V3StringSet m_future1s;     // argument: -future1 list
-    V3StringSet m_libraryFiles; // argument: Verilog -v files
+    VFileLibSet m_libraryFiles; // argument: Verilog -v files
     V3StringSet m_clockers;     // argument: Verilog -clk signals
     V3StringSet m_noClockers;   // argument: Verilog -noclk signals
-    V3StringList m_vFiles;      // argument: Verilog files to read
+    VFileLibList m_vFiles;      // argument: Verilog files to read
-    V3StringSet m_vltFiles;     // argument: Verilator config files to read
+    VFileLibSet m_vltFiles;     // argument: Verilator config files to read
     V3StringList m_forceIncs;   // argument: -FI
     DebugLevelMap m_debugLevel; // argument: --debugi-<srcfile/tag> <level>
     DebugLevelMap m_dumpLevel;  // argument: --dumpi-<srcfile/tag> <level>
@@ -359,7 +387,7 @@ private:
     string      m_diagnosticsSarifOutput;  // main switch: --diagnostics-sarif-output
     string      m_exeName;      // main switch: -o {name}
     string      m_flags;        // main switch: -f {name}
-    string      m_hierParamsFile; // main switch: --hierarchical-params-file
+    VFileLibList m_hierParamsFile; // main switch: --hierarchical-params-file
     string      m_jsonOnlyOutput;    // main switch: --json-only-output
     string      m_jsonOnlyMetaOutput;    // main switch: --json-only-meta-output
     string      m_l2Name;       // main switch: --l2name; "" for top-module's name
@@ -373,6 +401,7 @@ private:
     string      m_topModule;    // main switch: --top-module
     string      m_unusedRegexp; // main switch: --unused-regexp
     string      m_waiverOutput;  // main switch: --waiver-output {filename}
+    string      m_work = "work";  // main switch: --work {libname}
     string      m_xAssign;      // main switch: --x-assign
     string      m_xInitial;     // main switch: --x-initial
     string      m_xmlOutput;    // main switch: --xml-output
@@ -463,11 +492,11 @@ public:
     void addCompilerIncludes(const string& filename);
     void addLdLibs(const string& filename);
     void addMakeFlags(const string& filename);
-    void addLibraryFile(const string& filename);
+    void addLibraryFile(const string& filename, const string& libname);
     void addClocker(const string& signame);
     void addNoClocker(const string& signame);
-    void addVFile(const string& filename);
+    void addVFile(const string& filename, const string& libname);
-    void addVltFile(const string& filename);
+    void addVltFile(const string& filename, const string& libname);
     void addForceInc(const string& filename);
     bool available() const VL_MT_SAFE { return m_available; }
     void ccSet();
@@ -642,7 +671,7 @@ public:
                                                 : m_diagnosticsSarifOutput;
     }
     string exeName() const { return m_exeName != "" ? m_exeName : prefix(); }
-    string hierParamFile() const { return m_hierParamsFile; }
+    VFileLibList hierParamFile() const { return m_hierParamsFile; }
     string jsonOnlyOutput() const { return m_jsonOnlyOutput; }
     string jsonOnlyMetaOutput() const { return m_jsonOnlyMetaOutput; }
     string l2Name() const { return m_l2Name; }
@@ -668,6 +697,7 @@ public:
     bool noTraceTop() const { return m_noTraceTop; }
     string unusedRegexp() const { return m_unusedRegexp; }
     string waiverOutput() const { return m_waiverOutput; }
+    string work() const { return m_work; }
     bool isWaiverOutput() const { return !m_waiverOutput.empty(); }
     string xAssign() const { return m_xAssign; }
     string xInitial() const { return m_xInitial; }
@@ -678,9 +708,9 @@ public:
     const V3StringSet& compilerIncludes() const { return m_compilerIncludes; }
     const V3StringList& ldLibs() const { return m_ldLibs; }
     const V3StringList& makeFlags() const { return m_makeFlags; }
-    const V3StringSet& libraryFiles() const { return m_libraryFiles; }
+    const VFileLibSet& libraryFiles() const { return m_libraryFiles; }
-    const V3StringList& vFiles() const { return m_vFiles; }
+    const VFileLibList& vFiles() const { return m_vFiles; }
-    const V3StringSet& vltFiles() const { return m_vltFiles; }
+    const VFileLibSet& vltFiles() const { return m_vltFiles; }
     const V3StringList& forceIncs() const { return m_forceIncs; }
 
     bool hasParameter(const string& name);
@@ -690,7 +720,7 @@ public:
     bool isFuture(const string& flag) const;
     bool isFuture0(const string& flag) const;
     bool isFuture1(const string& flag) const;
-    bool isLibraryFile(const string& filename) const;
+    bool isLibraryFile(const string& filename, const string& libname) const;
     bool isClocker(const string& signame) const;
     bool isNoClocker(const string& signame) const;
 

src/V3Parse.h

@@ -43,7 +43,7 @@ public:
     // METHODS
     // Preprocess and read the Verilog file specified into the netlist database
     void parseFile(FileLine* fileline, const string& modname, bool inLibrary,
-                   const string& errmsg) VL_MT_DISABLED;
+                   const string& libname, const string& errmsg) VL_MT_DISABLED;
 
     // Push preprocessed text to the lexer
     static void ppPushText(V3ParseImp* impp, const string& text) VL_MT_DISABLED;

src/V3ParseImp.cpp

@@ -294,6 +294,7 @@ void V3ParseImp::preprocDumps(std::ostream& os, bool forInputs) {
 }
 
 void V3ParseImp::parseFile(FileLine* fileline, const string& modfilename, bool inLibrary,
+                           const string& libname,
                            const string& errmsg) {  // "" for no error, make fake node
     const string nondirname = V3Os::filenameNonDir(modfilename);
     const string modname = V3Os::filenameNonDirExt(modfilename);
@@ -303,13 +304,14 @@ void V3ParseImp::parseFile(FileLine* fileline, const string& modfilename, bool i
     m_lexFileline->newContent();
     m_bisonLastFileline = m_lexFileline;
     m_inLibrary = inLibrary;
+    m_libname = libname;
 
     // Preprocess into m_ppBuffer
     const bool ok = V3PreShell::preproc(fileline, modfilename, m_filterp, this, errmsg);
     if (!ok) {
         if (errmsg != "") return;  // Threw error already
         // Create fake node for later error reporting
-        AstNodeModule* const nodep = new AstNotFoundModule{fileline, modname};
+        AstNodeModule* const nodep = new AstNotFoundModule{fileline, modname, libname};
         v3Global.rootp()->addModulesp(nodep);
         return;
     }
@@ -745,8 +747,8 @@ V3Parse::~V3Parse() {  //
     VL_DO_CLEAR(delete m_impp, m_impp = nullptr);
 }
 void V3Parse::parseFile(FileLine* fileline, const string& modname, bool inLibrary,
-                        const string& errmsg) {
+                        const string& libname, const string& errmsg) {
-    m_impp->parseFile(fileline, modname, inLibrary, errmsg);
+    m_impp->parseFile(fileline, modname, inLibrary, libname, errmsg);
 }
 void V3Parse::ppPushText(V3ParseImp* impp, const string& text) {
     if (text != "") impp->ppPushText(text);

src/V3ParseImp.h

@@ -150,6 +150,7 @@ class V3ParseImp final {
     FileLine* m_bisonLastFileline = nullptr;  // Filename/linenumber of last token
 
     bool m_inLibrary = false;  // Currently reading a library vs. regular file
+    string m_libname;  // Config library name (or --work)
     int m_lexKwdDepth = 0;  // Inside a `begin_keywords
     int m_lexKwdLast;  // Last LEX state in `begin_keywords
     VOptionBool m_unconnectedDrive;  // Last unconnected drive
@@ -254,6 +255,7 @@ public:
     // Return next token, for bison, since bison isn't class based, use a global THIS
     AstNetlist* rootp() const { return m_rootp; }
     bool inLibrary() const { return m_inLibrary; }
+    string libname() const { return m_libname; }
     VOptionBool unconnectedDrive() const { return m_unconnectedDrive; }
     void unconnectedDrive(const VOptionBool flag) { m_unconnectedDrive = flag; }
 
@@ -287,7 +289,7 @@ public:
     int tokenToBison() VL_MT_DISABLED;  // Pass token to bison
 
     void parseFile(FileLine* fileline, const string& modfilename, bool inLibrary,
-                   const string& errmsg) VL_MT_DISABLED;
+                   const string& libname, const string& errmsg) VL_MT_DISABLED;
     void dumpInputsFile() VL_MT_DISABLED;
     static void candidatePli(VSpellCheck* spellerp) VL_MT_DISABLED;
 

src/verilog.y

@@ -1250,7 +1250,7 @@ package_declaration:            // ==IEEE: package_declaration
 
 packageFront<nodeModulep>:
                 yPACKAGE lifetimeE idAny ';'
-                        { $$ = new AstPackage{$<fl>3, *$3};
+                        { $$ = new AstPackage{$<fl>3, *$3, PARSEP->libname()};
                           if ($$->name() == "std") {
                               if ($$->fileline()->filename() != V3Options::getStdPackagePath()) {
                                   $$->v3error("Redeclaring the 'std' package is not allowed");
@@ -1394,7 +1394,7 @@ modFront<nodeModulep>:
         //                      // General note: all *Front functions must call symPushNew before
         //                      // any formal arguments, as the arguments must land in the new scope.
                 yMODULE lifetimeE idAny
-                        { $$ = new AstModule{$<fl>3, *$3};
+                        { $$ = new AstModule{$<fl>3, *$3, PARSEP->libname()};
                           $$->lifetime($2);
                           $$->inLibrary(PARSEP->inLibrary() || $$->fileline()->celldefineOn());
                           $$->modTrace(GRAMMARP->allTracingOn($$->fileline()));
@@ -1415,7 +1415,7 @@ importsAndParametersE<nodep>:   // IEEE: common part of module_declaration, inte
 
 udpFront<nodeModulep>:
                 yPRIMITIVE lifetimeE idAny
-                        { $$ = new AstPrimitive{$<fl>3, *$3};
+                        { $$ = new AstPrimitive{$<fl>3, *$3, PARSEP->libname()};
                           $$->inLibrary(true);
                           $$->lifetime($2);
                           $$->modTrace(false);
@@ -1685,7 +1685,7 @@ interface_declaration:          // IEEE: interface_declaration + interface_nonan
 
 intFront<nodeModulep>:
                 yINTERFACE lifetimeE idAny/*new_interface*/
-                        { $$ = new AstIface{$<fl>3, *$3};
+                        { $$ = new AstIface{$<fl>3, *$3, PARSEP->libname()};
                           $$->inLibrary(true);
                           $$->lifetime($2);
                           PARSEP->rootp()->addModulesp($$); }
@@ -1772,7 +1772,7 @@ program_declaration:            // IEEE: program_declaration + program_nonansi_h
 
 pgmFront<nodeModulep>:
                 yPROGRAM lifetimeE idAny/*new_program*/
-                        { $$ = new AstModule{$<fl>3, *$3, AstModule::Program{}};
+                        { $$ = new AstModule{$<fl>3, *$3, PARSEP->libname(), AstModule::Program{}};
                           $$->lifetime($2);
                           $$->inLibrary(PARSEP->inLibrary() || $$->fileline()->celldefineOn());
                           $$->modTrace(GRAMMARP->allTracingOn($$->fileline()));
@@ -6792,7 +6792,7 @@ covergroup_declaration<nodep>:  // ==IEEE: covergroup_declaration
 
 covergroup_declarationFront<classp>:  // IEEE: part of covergroup_declaration
                 yCOVERGROUP idAny
-                        { $$ = new AstClass{$<fl>2, *$2};
+                        { $$ = new AstClass{$<fl>2, *$2, PARSEP->libname()};
                           BBCOVERIGN($<fl>1, "Ignoring unsupported: covergroup"); }
         ;
 
@@ -7196,7 +7196,7 @@ checker_declaration<nodeModulep>:  // ==IEEE: part of checker_declaration
 
 checkerFront<nodeModulep>:  // IEEE: part of checker_declaration
                 yCHECKER idAny/*checker_identifier*/
-                        { $$ = new AstModule{$<fl>2, *$2, AstModule::Checker{}};
+                        { $$ = new AstModule{$<fl>2, *$2, PARSEP->libname(), AstModule::Checker{}};
                           $$->modTrace(GRAMMARP->allTracingOn($$->fileline()));
                           $$->timeunit(PARSEP->timeLastUnit());
                           $$->unconnectedDrive(PARSEP->unconnectedDrive()); }
@@ -7327,14 +7327,14 @@ class_declaration<nodep>:       // ==IEEE: part of class_declaration
 classFront<classp>:             // IEEE: part of class_declaration
         //                      // IEEE 1800-2023: lifetimeE replaced with final_specifierE
                 classVirtualE yCLASS final_specifierE lifetimeE idAny/*class_identifier*/
-                        { $$ = new AstClass{$2, *$5};
+                        { $$ = new AstClass{$2, *$5, PARSEP->libname()};
                           $$->baseOverride($3);
                           $$->isVirtual($1);
                           v3Global.setHasClasses(); }
         //                      // IEEE: part of interface_class_declaration
         //                      // IEEE 1800-2023: lifetimeE removed
         |       yINTERFACE yCLASS idAny/*class_identifier*/
-                        { $$ = new AstClass{$2, *$3};
+                        { $$ = new AstClass{$2, *$3, PARSEP->libname()};
                           $$->isInterfaceClass(true);
                           v3Global.setHasClasses(); }
         ;

test_regress/t/t_config_work.out

@@ -0,0 +1,5 @@
+*-* All Finished *-*
+liba:m1 %m=t.u_1 %l=liba.m1
+liba:m3 %m=t.u_1.u_13 %l=liba.m3
+libb:m2 %m=t.u_2 %l=libb.m2
+libb:m3 %m=t.u_2.u_23 %l=libb.m3

test_regress/t/t_config_work.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2025 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile(
+    verilator_flags2=['--binary', '--work liba', 't/t_config_work__liba.v', '--work libb', 't/t_config_work__libb.v'])
+
+test.execute()
+
+# Sort so that 'initial' scheduling order is not relevant
+test.files_identical_sorted(test.run_log_filename, test.golden_filename, is_logfile=True)
+
+test.passes()

test_regress/t/t_config_work.v

@@ -0,0 +1,11 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+   m1 u_1();
+   m2 u_2();
+   final $write("*-* All Finished *-*\n");
+endmodule

test_regress/t/t_config_work__liba.v

@@ -0,0 +1,14 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module m1;
+  m3 u_13();
+  initial $display("liba:m1 %%m=%m %%l=%l");
+endmodule
+
+module m3;  // Module name duplicated between libraries
+  initial $display("liba:m3 %%m=%m %%l=%l");
+endmodule

test_regress/t/t_config_work__libb.v

@@ -0,0 +1,14 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module m2;
+  m3 u_23();
+  initial $display("libb:m2 %%m=%m %%l=%l");
+endmodule
+
+module m3;  // Module name duplicated between libraries
+  initial $display("libb:m3 %%m=%m %%l=%l");
+endmodule

test_regress/t/t_display.out

@@ -1,8 +1,8 @@
 [0] In top.t: Hi
-[0] In top.t.sub.write_m (sub)
+[0] In top.t.sub.write_m (work.sub)
-[0] In top.t.sub.write_m.subblock (sub)
+[0] In top.t.sub.write_m.subblock (work.sub)
-[0] In top.t.sub2.write_m (sub2)
+[0] In top.t.sub2.write_m (work.sub2)
-[0] In top.t.sub2.write_m.subblock2 (sub2)
+[0] In top.t.sub2.write_m.subblock2 (work.sub2)
 a: -0.4=> 0.4  0  0  0
 [0] Back \ Quote "
 [0] %b=000001100 %0b=1100  %b=00000101010111011101110111100110011001100 %0b=101010111011101110111100110011001100  %b=000001010101111000001001000110100010101100111100000010010001101000101011001111000 %0b=1010101111000001001000110100010101100111100000010010001101000101011001111000

test_regress/t/t_sys_sformat.v

@@ -58,7 +58,7 @@ module t;
 
       $swrite(str2, "lib=%l");
 `ifdef TEST_VERBOSE  $display("chkl %0s",str2);  `endif
-      if (str2 !== "lib=t") $stop;
+      if (str2 !== "lib=work.t") $stop;
 
       str3 = $sformatf("u=%u", {"a","b","c","d"}); // Value selected so is printable
 `ifdef TEST_VERBOSE  $display("chku %s", str3);  `endif