From 1c0739db10cd5aa02dd495aca1f592269b76481a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Risto=20Peja=C5=A1inovi=C4=87?=
 <risto.pejasinovic@gmail.com>
Date: Mon, 29 May 2023 18:08:39 +0200
Subject: [PATCH] Fix unpacked struct == and != operators (#4234) (#4240)

---
 src/V3EmitCHeaders.cpp                 | 23 ++++++++++++
 test_regress/t/t_unpacked_struct_eq.pl | 21 +++++++++++
 test_regress/t/t_unpacked_struct_eq.v  | 51 ++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100755 test_regress/t/t_unpacked_struct_eq.pl
 create mode 100644 test_regress/t/t_unpacked_struct_eq.v

diff --git a/src/V3EmitCHeaders.cpp b/src/V3EmitCHeaders.cpp
index 4d2a77d60..abda6f4f1 100644
--- a/src/V3EmitCHeaders.cpp
+++ b/src/V3EmitCHeaders.cpp
@@ -22,7 +22,9 @@
 #include "V3Global.h"
 
 #include <algorithm>
+#include <cstdint>
 #include <set>
+#include <string>
 #include <vector>
 
 VL_DEFINE_DEBUG_FUNCTIONS;
@@ -236,6 +238,27 @@ class EmitCHeader final : public EmitCConstInit {
             puts(itemp->dtypep()->cType(itemp->nameProtect(), false, false));
             puts(";\n");
         }
+
+        puts("\nbool operator==(const " + EmitCBase::prefixNameProtect(sdtypep) + "& rhs){\n");
+        puts("return ");
+        for (const AstMemberDType* itemp = sdtypep->membersp(); itemp;
+             itemp = VN_AS(itemp->nextp(), MemberDType)) {
+            if (itemp != sdtypep->membersp()) puts("\n    && ");
+            if (AstUnpackArrayDType* const adtypep
+                = VN_CAST(itemp->subDTypep(), UnpackArrayDType)) {
+                for (uint32_t i = 0; i < adtypep->arrayUnpackedElements(); i++) {
+                    if (i != 0) puts("\n    && ");
+                    puts(itemp->nameProtect() + "[" + std::to_string(i) + "U] == " + "rhs."
+                         + itemp->nameProtect() + "[" + std::to_string(i) + "U]");
+                }
+            } else {
+                puts(itemp->nameProtect() + " == " + "rhs." + itemp->nameProtect());
+            }
+        }
+        puts(";\n");
+        puts("}\n");
+        puts("bool operator!=(const " + EmitCBase::prefixNameProtect(sdtypep) + "& rhs){\n");
+        puts("return !(*this == rhs);\n}\n");
         puts("};\n");
     }
     void emitStructs(const AstNodeModule* modp) {
diff --git a/test_regress/t/t_unpacked_struct_eq.pl b/test_regress/t/t_unpacked_struct_eq.pl
new file mode 100755
index 000000000..a17622844
--- /dev/null
+++ b/test_regress/t/t_unpacked_struct_eq.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2004 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
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_unpacked_struct_eq.v b/test_regress/t/t_unpacked_struct_eq.v
new file mode 100644
index 000000000..726922e24
--- /dev/null
+++ b/test_regress/t/t_unpacked_struct_eq.v
@@ -0,0 +1,51 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Use this file as a template for submitting bugs, etc.
+// This module takes a single clock input, and should either
+//      $write("*-* All Finished *-*\n");
+//      $finish;
+// on success, or $stop.
+//
+// The code as shown applies a random vector to the Test
+// module, then calculates a CRC on the Test module's outputs.
+//
+// **If you do not wish for your code to be released to the public
+// please note it here, otherwise:**
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+    typedef struct {
+        string txt;
+        struct {
+            logic m0;
+            logic [3:0] m1;
+        } sub;
+        logic [7:0] arr[2];
+    } struct_t;
+    struct_t s1;
+    struct_t s2;
+
+    assign {s1.sub.m0, s1.sub.m1} = {1'b0, 4'h5};
+    assign {s2.sub.m0, s2.sub.m1} = {1'b0, 4'h5};
+    assign s1.txt = "text";
+    assign s2.txt = "text";
+    assign s1.arr[0] = 8'h77;
+    assign s2.arr[0] = 8'h77;
+    assign s1.arr[1] = 8'h33;
+    assign s2.arr[1] = 8'h33;
+
+    initial begin
+        if(s1 != s2) begin
+            $fatal;
+        end
+        if(s1 == s2) begin
+            $write("*-* All Finished *-*\n");
+            $finish;
+        end else begin
+            $fatal;
+        end
+    end
+endmodule