Fix unpacked array concatenation function arguments (#6900)

src/V3Task.cpp

@@ -32,6 +32,7 @@
 #include "V3EmitCBase.h"
 #include "V3Graph.h"
 #include "V3Stats.h"
+#include "V3UniqueNames.h"
 
 #include <tuple>
 
@@ -393,6 +394,8 @@ class TaskVisitor final : public VNVisitor {
 
     // STATE
     TaskStateVisitor* const m_statep;  // Common state between visitors
+    V3UniqueNames m_initArrayTmpNames;  // For generating unique temporary variable names for
+                                        // arguments being AstInitArray
     AstNodeModule* m_modp = nullptr;  // Current module
     AstTopScope* const m_topScopep = v3Global.rootp()->topScopep();  // The AstTopScope
     AstScope* m_scopep = nullptr;  // Current scope
@@ -1441,6 +1444,29 @@ class TaskVisitor final : public VNVisitor {
         UINFOTREE(9, newp, "", "newfunc");
         m_insStmtp->addHereThisAsNext(newp);
     }
+    void processPins(AstNodeFTaskRef* nodep) {
+        // Create a fresh variable for each concat array present in pins list
+        for (AstNode* pinp = nodep->pinsp(); pinp; pinp = pinp->nextp()) {
+            AstArg* const argp = VN_AS(pinp, Arg);
+            AstInitArray* const arrayp = VN_CAST(argp->exprp(), InitArray);
+            if (!arrayp) continue;
+
+            FileLine* const flp = arrayp->fileline();
+            const std::string tempName = m_initArrayTmpNames.get(argp);
+            AstVar* const substp = new AstVar{flp, VVarType::VAR, tempName, arrayp->dtypep()};
+            substp->funcLocal(true);
+            AstVarScope* const substvscp = createVarScope(substp, tempName);
+
+            AstAssign* const assignp
+                = new AstAssign{flp, new AstVarRef{arrayp->fileline(), substvscp, VAccess::WRITE},
+                                arrayp->unlinkFrBack()};
+
+            AstExprStmt* const exprstmtp = new AstExprStmt{
+                flp, substp, new AstVarRef{arrayp->fileline(), substvscp, VAccess::READ}};
+            exprstmtp->stmtsp()->addNext(assignp);
+            argp->exprp(exprstmtp);
+        }
+    }
 
     // VISITORS
     void visit(AstNodeModule* nodep) override {
@@ -1497,6 +1523,7 @@ class TaskVisitor final : public VNVisitor {
         AstNode* beginp;
         AstCNew* cnewp = nullptr;
         if (m_statep->ftaskNoInline(nodep->taskp())) {
+            processPins(nodep);
             // This may share VarScope's with a public task, if any.  Yuk.
             beginp = createNonInlinedFTask(nodep, namePrefix, outvscp, cnewp /*ref*/);
         } else {
@@ -1672,7 +1699,8 @@ class TaskVisitor final : public VNVisitor {
 public:
     // CONSTRUCTORS
     TaskVisitor(AstNetlist* nodep, TaskStateVisitor* statep)
-        : m_statep{statep} {
+        : m_statep{statep}
+        , m_initArrayTmpNames{"__VInitArrayTemp"} {
         iterate(nodep);
     }
     ~TaskVisitor() {

test_regress/t/t_concat_init_array_functions.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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()
+
+test.execute()
+
+test.passes()

test_regress/t/t_concat_init_array_functions.v

@@ -0,0 +1,50 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Simple test for unpacked concatenation arrays used as function arguments.
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2026 by Antmicro.
+// SPDX-License-Identifier: CC0-1.0
+//
+
+class A;
+  int r1[2];
+  int r2;
+endclass
+
+class B;
+  virtual function int B_virt_func(int r[3], p[4]);
+    return r[0] + r[1] + r[2] + p[0] + p[1] + p[2] + p[3];
+  endfunction
+endclass
+
+function int func_1_concat(int r[4]);
+// verilator no_inline_task
+  return r[0] + r[1] + r[2] + r[3];
+endfunction
+
+function int func_2_concat(int r[3], int p[4]);
+// verilator no_inline_task
+  return r[0] + r[1] + r[2] + p[0] + p[1] + p[2] + p[3];
+endfunction
+
+module t;
+  int s;
+  A a = new;
+  B b = new;
+  initial begin
+    a.r1 = {1,2};
+    a.r2 = 5;
+    s = func_1_concat({a.r1, a.r1});
+    if (s != 6) $stop;
+
+    s = func_2_concat({a.r1, a.r2}, {a.r1, a.r1});
+    if (s != 14) $stop;
+
+    s = b.B_virt_func({a.r1, a.r2}, {a.r1, a.r1});
+    if (s != 14) $stop;
+
+    $write("*-* All finished *-*\n");
+    $finish;
+  end
+endmodule