Support interface classes and class implements.

Changes

@@ -14,6 +14,7 @@ Verilator 5.007 devel
 **Minor:**
 
 * Support unpacked unions.
+* Support interface classes and class implements.
 * Support global clocking and $global_clock.
 
 

src/V3LinkDot.cpp

@@ -748,7 +748,6 @@ class LinkDotFindVisitor final : public VNVisitor {
     string m_scope;  // Scope text
     const AstNodeBlock* m_blockp = nullptr;  // Current Begin/end block
     const AstNodeFTask* m_ftaskp = nullptr;  // Current function/task
-    bool m_inInterfaceClass = false;  // Inside a class interface
     bool m_inRecursion = false;  // Inside a recursive module
     int m_paramNum = 0;  // Parameter number, for position based connection
     bool m_explicitNew = false;  // Hit a "new" function
@@ -917,9 +916,6 @@ class LinkDotFindVisitor final : public VNVisitor {
     void visit(AstClass* nodep) override {
         UASSERT_OBJ(m_curSymp, nodep, "Class not under module/package/$unit");
         UINFO(8, "   " << nodep << endl);
-        if (nodep->isInterfaceClass()) {
-            nodep->v3warn(E_UNSUPPORTED, "Unsupported: interface classes");
-        }
         // Remove classes that have void params, as they were only used for the parameterization
         // step and will not be instantiated
         if (m_statep->removeVoidParamedClasses()) {
@@ -934,7 +930,6 @@ class LinkDotFindVisitor final : public VNVisitor {
         }
         VL_RESTORER(m_scope);
         VL_RESTORER(m_classOrPackagep);
-        VL_RESTORER(m_inInterfaceClass);
         VL_RESTORER(m_modSymp);
         VL_RESTORER(m_curSymp);
         VL_RESTORER(m_paramNum);
@@ -945,7 +940,6 @@ class LinkDotFindVisitor final : public VNVisitor {
             VSymEnt* const upperSymp = m_curSymp;
             m_scope = m_scope + "." + nodep->name();
             m_classOrPackagep = nodep;
-            m_inInterfaceClass = nodep->isInterfaceClass();
             m_curSymp = m_modSymp
                 = m_statep->insertBlock(upperSymp, nodep->name(), nodep, m_classOrPackagep);
             m_statep->insertMap(m_curSymp, m_scope);
@@ -1074,9 +1068,11 @@ class LinkDotFindVisitor final : public VNVisitor {
         VL_RESTORER(m_curSymp);
         VSymEnt* upSymp = m_curSymp;
         {
-            if (m_inInterfaceClass && !nodep->pureVirtual()) {
+            if (VN_IS(m_curSymp->nodep(), Class)
+                && VN_AS(m_curSymp->nodep(), Class)->isInterfaceClass() && !nodep->pureVirtual()
+                && !nodep->isConstructor()) {
                 nodep->v3error("Interface class functions must be pure virtual"
-                               << " (IEEE 1800-2017 8.26)");
+                               << " (IEEE 1800-2017 8.26): " << nodep->prettyNameQ());
             }
             // Change to appropriate package if extern declaration (vs definition)
             if (nodep->classOrPackagep()) {
@@ -1200,10 +1196,10 @@ class LinkDotFindVisitor final : public VNVisitor {
         // Var: Remember its name for later resolution
         UASSERT_OBJ(m_curSymp && m_modSymp, nodep, "Var not under module?");
         iterateChildren(nodep);
-        if (m_inInterfaceClass && !nodep->isParam() && !nodep->isFuncLocal()
+        if (VN_IS(m_curSymp->nodep(), Class)
-            && !nodep->isFuncReturn()) {
+            && VN_AS(m_curSymp->nodep(), Class)->isInterfaceClass() && !nodep->isParam()) {
             nodep->v3error("Interface class cannot contain non-parameter members"
-                           << " (IEEE 1800-2017 8.26)");
+                           << " (IEEE 1800-2017 8.26): " << nodep->prettyNameQ());
         }
         if (!m_statep->forScopeCreation()) {
             // Find under either a task or the module's vars
@@ -2026,6 +2022,7 @@ private:
     AstNodeFTask* m_ftaskp = nullptr;  // Current function/task
     int m_modportNum = 0;  // Uniqueify modport numbers
     bool m_inSens = false;  // True if in senitem
+    std::set<std::string> m_ifClassImpNames;  // Names imported from interface class
 
     struct DotStates {
         DotPosition m_dotPos;  // Scope part of dotted resolution
@@ -2179,7 +2176,45 @@ private:
         } while (classSymp && !VN_IS(classSymp->nodep(), Class));
         return classSymp;
     }
-
+    void importImplementsClass(AstClass* implementsClassp, VSymEnt* interfaceSymp,
+                               AstClass* interfaceClassp) {
+        UINFO(8, "importImplementsClass to " << implementsClassp << " from " << interfaceClassp
+                                             << endl);
+        for (VSymEnt::const_iterator it = interfaceSymp->begin(); it != interfaceSymp->end();
+             ++it) {
+            if (AstNode* interfaceSubp = it->second->nodep()) {
+                UINFO(8, "  SymFunc " << interfaceSubp << endl);
+                if (VN_IS(interfaceSubp, NodeFTask)) {
+                    bool existsInChild = m_curSymp->findIdFlat(interfaceSubp->name());
+                    if (!existsInChild && !implementsClassp->isInterfaceClass()) {
+                        implementsClassp->v3error(
+                            "Class " << implementsClassp->prettyNameQ() << " implements "
+                                     << interfaceClassp->prettyNameQ()
+                                     << " but is missing implementation for "
+                                     << interfaceSubp->prettyNameQ() << " (IEEE 1800-2017 8.26)\n"
+                                     << implementsClassp->warnContextPrimary() << '\n'
+                                     << interfaceSubp->warnOther()
+                                     << "... Location of interface class's function\n"
+                                     << interfaceSubp->warnContextSecondary());
+                    }
+                    if (m_ifClassImpNames.find(interfaceSubp->name()) != m_ifClassImpNames.end()
+                        && !existsInChild) {
+                        implementsClassp->v3error(
+                            "Class " << implementsClassp->prettyNameQ() << " implements "
+                                     << interfaceClassp->prettyNameQ()
+                                     << " but missing inheritance conflict resolution for "
+                                     << interfaceSubp->prettyNameQ()
+                                     << " (IEEE 1800-2017 8.26.6.2)\n"
+                                     << implementsClassp->warnContextPrimary() << '\n'
+                                     << interfaceSubp->warnOther()
+                                     << "... Location of interface class's function\n"
+                                     << interfaceSubp->warnContextSecondary());
+                    }
+                    m_ifClassImpNames.emplace(interfaceSubp->name());
+                }
+            }
+        }
+    }
     // VISITs
     void visit(AstNetlist* nodep) override {
         // Recurse..., backward as must do packages before using packages
@@ -3186,15 +3221,21 @@ private:
         checkNoDot(nodep);
         VL_RESTORER(m_curSymp);
         VL_RESTORER(m_modSymp);
+        VL_RESTORER(m_ifClassImpNames);
         {
             m_ds.init(m_curSymp);
             // Until overridden by a SCOPE
             m_ds.m_dotSymp = m_curSymp = m_modSymp = m_statep->getNodeSym(nodep);
             m_modp = nodep;
+            int next = 0;
             for (AstNode* itemp = nodep->extendsp(); itemp; itemp = itemp->nextp()) {
                 if (AstClassExtends* const cextp = VN_CAST(itemp, ClassExtends)) {
                     // Replace abstract reference with hard pointer
                     // Will need later resolution when deal with parameters
+                    if (++next == 2 && !nodep->isInterfaceClass() && !cextp->isImplements()) {
+                        cextp->v3error("Multiple inheritance illegal on non-interface classes"
+                                       " (IEEE 1800-2017 8.13)");
+                    }
                     if (cextp->childDTypep() || cextp->dtypep()) continue;  // Already converted
                     AstClassOrPackageRef* const cpackagerefp
                         = VN_CAST(cextp->classOrPkgsp(), ClassOrPackageRef);
@@ -3256,7 +3297,11 @@ private:
                                     classp->isExtended(true);
                                     nodep->isExtended(true);
                                     VSymEnt* const srcp = m_statep->getNodeSym(classp);
-                                    m_curSymp->importFromClass(m_statep->symsp(), srcp);
+                                    if (classp->isInterfaceClass()) {
+                                        importImplementsClass(nodep, srcp, classp);
+                                    } else {
+                                        m_curSymp->importFromClass(m_statep->symsp(), srcp);
+                                    }
                                     VL_DO_DANGLING(cpackagerefp->unlinkFrBack()->deleteTree(),
                                                    cpackagerefp);
                                 }

src/V3Width.cpp

@@ -3624,7 +3624,7 @@ private:
                 // Either made explicitly or V3LinkDot made implicitly
                 classp->v3fatalSrc("Can't find class's new");
             }
-            if (classp->isVirtual()) {
+            if (classp->isVirtual() || classp->isInterfaceClass()) {
                 nodep->v3error(
                     "Illegal to call 'new' using an abstract virtual class (IEEE 1800-2017 8.21)");
             }

src/V3WidthCommit.h

@@ -214,8 +214,9 @@ private:
     void visit(AstNodeFTask* nodep) override {
         iterateChildren(nodep);
         editDType(nodep);
-        if (nodep->classMethod() && nodep->pureVirtual() && VN_IS(m_modp, Class)
+        AstClass* classp = VN_CAST(m_modp, Class);
-            && !VN_AS(m_modp, Class)->isVirtual()) {
+        if (nodep->classMethod() && nodep->pureVirtual() && classp && !classp->isInterfaceClass()
+            && !classp->isVirtual()) {
             nodep->v3error(
                 "Illegal to have 'pure virtual' in non-virtual class (IEEE 1800-2017 8.21)");
         }

src/verilog.y

@@ -6504,10 +6504,7 @@ classExtendsE<classExtendsp>:           // IEEE: part of class_declaration
 
 classExtendsList<classExtendsp>:        // IEEE: part of class_declaration
                 classExtendsOne                         { $$ = $1; $<scp>$ = $<scp>1; }
-        |       classExtendsList ',' classExtendsOne
+        |       classExtendsList ',' classExtendsOne    { $$ = addNextNull($1, $3); $<scp>$ = $<scp>3; }
-                        { $$ = $3; $<scp>$ = $<scp>3;
-                          BBUNSUP($3, "Multiple inheritance illegal on non-interface classes (IEEE 1800-2017 8.13), "
-                                      "and unsupported for interface classes."); }
         ;
 
 classExtendsOne<classExtendsp>:         // IEEE: part of class_declaration

test_regress/t/t_class_extends_bad.out

@@ -1,5 +1,4 @@
-%Error-UNSUPPORTED: t/t_class_extends_bad.v:13:26: Multiple inheritance illegal on non-interface classes (IEEE 1800-2017 8.13), and unsupported for interface classes.
+%Error: t/t_class_extends_bad.v:13:26: Multiple inheritance illegal on non-interface classes (IEEE 1800-2017 8.13)
    13 | class Cls extends Base1, Base2;
       |                          ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
 %Error: Exiting due to

test_regress/t/t_implements.out

@@ -1,14 +0,0 @@
-%Error-UNSUPPORTED: t/t_implements.v:7:11: Unsupported: interface classes
-    7 | interface class Icempty;
-      |           ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
-%Error-UNSUPPORTED: t/t_implements.v:10:11: Unsupported: interface classes
-   10 | interface class Icls1;
-      |           ^~~~~
-%Error-UNSUPPORTED: t/t_implements.v:17:11: Unsupported: interface classes
-   17 | interface class Iext1 extends Icls1;
-      |           ^~~~~
-%Error-UNSUPPORTED: t/t_implements.v:21:11: Unsupported: interface classes
-   21 | interface class Icls2;
-      |           ^~~~~
-%Error: Exiting due to

test_regress/t/t_implements.pl

@@ -11,13 +11,7 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(simulator => 1);
 
 compile(
-    fails => $Self->{vlt_all},
-    expect_filename => $Self->{golden_filename},
     );
 
-execute(
-    check_finished => 1,
-    ) if !$Self->{vlt_all};
-
 ok(1);
 1;

test_regress/t/t_implements.v

@@ -19,25 +19,25 @@ interface class Iext1 extends Icls1;
 endclass
 
 interface class Icls2;
-   pure virtual function int icf2;
+   pure virtual function int icf2(int in);
    pure virtual function int icfboth;
 endclass
 
-   virtual class Base implements Iext1, Icls2;
+virtual class Base implements Iext1, Icls2;
-      virtual function int icf1;
+   virtual function int icf1;
-         return 1;
+      return 1;
-      endfunction
+   endfunction
-      virtual function int icf101;
+   virtual function int icf101;
-         return 101;
+      return 101;
-      endfunction
+   endfunction
-      virtual function int icf2;
+   virtual function int icf2(int in);
-         return 2;
+      return in + 2;
-      endfunction
+   endfunction
-      virtual function int icfboth;
+   virtual function int icfboth;
-         return 3;
+      return 3;
-      endfunction
+   endfunction
-      pure virtual function int icfpartial;
+   pure virtual function int icfpartial;
-   endclass
+endclass
 
 class Cls extends Base;
    virtual function int icfpartial;
@@ -56,7 +56,7 @@ module t(/*AUTOARG*/);
       c = new;
       if (c.icf1() != 1) $stop;
       if (c.icf101() != 101) $stop;
-      if (c.icf2() != 2) $stop;
+      if (c.icf2(1000) != 1002) $stop;
       if (c.icfpartial() != 62) $stop;
 
       i1 = c;

test_regress/t/t_implements_collision.out

@@ -1,5 +0,0 @@
-%Error-UNSUPPORTED: t/t_implements_collision.v:15:41: Multiple inheritance illegal on non-interface classes (IEEE 1800-2017 8.13), and unsupported for interface classes.
-   15 | interface class IclsBoth extends Icls1, Icls2;
-      |                                         ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
-%Error: Exiting due to

test_regress/t/t_implements_collision.pl

@@ -2,7 +2,7 @@
 if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
 # DESCRIPTION: Verilator: Verilog Test driver/expect definition
 #
-# Copyright 2019 by Wilson Snyder. This program is free software; you
+# Copyright 2023 by Wilson Snyder. This program is free software; you
 # can redistribute it and/or modify it under the terms of either the GNU
 # Lesser General Public License Version 3 or the Perl Artistic License
 # Version 2.0.
@@ -11,13 +11,11 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(simulator => 1);
 
 compile(
-    fails => $Self->{vlt_all},
-    expect_filename => $Self->{golden_filename},
     );
 
 execute(
     check_finished => 1,
-    ) if !$Self->{vlt_all};
+    );
 
 ok(1);
 1;

test_regress/t/t_implements_collision.v

@@ -28,7 +28,7 @@ module t(/*AUTOARG*/);
 
    initial begin
       c = new;
-      if (c.ifcboth() != 3) $stop;
+      if (c.icfboth() != 3) $stop;
 
       $write("*-* All Finished *-*\n");
       $finish;

test_regress/t/t_implements_collision_bad.out

@@ -1,5 +1,7 @@
-%Error-UNSUPPORTED: t/t_implements_collision_bad.v:15:41: Multiple inheritance illegal on non-interface classes (IEEE 1800-2017 8.13), and unsupported for interface classes.
+%Error: t/t_implements_collision_bad.v:15:11: Class 'IclsBoth' implements 'Icls2' but missing inheritance conflict resolution for 'icfboth' (IEEE 1800-2017 8.26.6.2)
    15 | interface class IclsBoth extends Icls1, Icls2;
-      |                                         ^~~~~
+      |           ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+        t/t_implements_collision_bad.v:12:30: ... Location of interface class's function
+   12 |    pure virtual function int icfboth;
+      |                              ^~~~~~~
 %Error: Exiting due to

test_regress/t/t_implements_contents_bad.out

@@ -1,11 +1,7 @@
-%Error-UNSUPPORTED: t/t_implements_contents_bad.v:7:11: Unsupported: interface classes
+%Error: t/t_implements_contents_bad.v:8:8: Interface class cannot contain non-parameter members (IEEE 1800-2017 8.26): 'badi'
-    7 | interface class Icls;
-      |           ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
-%Error: t/t_implements_contents_bad.v:8:8: Interface class cannot contain non-parameter members (IEEE 1800-2017 8.26)
     8 |    int badi;
       |        ^~~~
-%Error: t/t_implements_contents_bad.v:9:9: Interface class functions must be pure virtual (IEEE 1800-2017 8.26)
+%Error: t/t_implements_contents_bad.v:9:9: Interface class functions must be pure virtual (IEEE 1800-2017 8.26): 'badtask'
     9 |    task badtask;
       |         ^~~~~~~
 %Error: Exiting due to

test_regress/t/t_implements_missing_bad.out

@@ -1,5 +1,7 @@
-%Error-UNSUPPORTED: t/t_implements_missing_bad.v:7:11: Unsupported: interface classes
+%Error: t/t_implements_missing_bad.v:12:1: Class 'Cls' implements 'Icls1' but is missing implementation for 'icf2' (IEEE 1800-2017 8.26)
-    7 | interface class Icls1;
+   12 | class Cls implements Icls1;
-      |           ^~~~~
+      | ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+        t/t_implements_missing_bad.v:9:30: ... Location of interface class's function
+    9 |    pure virtual function int icf2;
+      |                              ^~~~
 %Error: Exiting due to

test_regress/t/t_implements_new_bad.out

@@ -1,5 +1,5 @@
-%Error-UNSUPPORTED: t/t_implements_new_bad.v:7:11: Unsupported: interface classes
+%Error: t/t_implements_new_bad.v:13:11: Illegal to call 'new' using an abstract virtual class (IEEE 1800-2017 8.21)
-    7 | interface class Icls;
+                                      : ... In instance t
-      |           ^~~~~
+   13 |       c = new;   
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+      |           ^~~
 %Error: Exiting due to

test_regress/t/t_implements_noinherit_bad.out

@@ -1,5 +1,4 @@
-%Error-UNSUPPORTED: t/t_implements_noinherit_bad.v:7:11: Unsupported: interface classes
+%Error: t/t_implements_noinherit_bad.v:14:16: Can't find definition of variable: 'IP'
-    7 | interface class Icls;
+   14 |       $display(IP);  
-      |           ^~~~~
+      |                ^~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
 %Error: Exiting due to

test_regress/t/t_implements_noninterface_bad.out

@@ -1,7 +1,3 @@
-%Error-UNSUPPORTED: t/t_implements_noninterface_bad.v:13:11: Unsupported: interface classes
-   13 | interface class Icls;
-      |           ^~~~~
-                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
 %Error: t/t_implements_noninterface_bad.v:10:26: Attempting to implement from non-interface class 'NotIcls'
 ... Suggest use 'extends'
    10 | class ClsBad1 implements NotIcls;