From ad55564905cd188810f79c7abb92adf69bbf7023 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Mon, 29 Jun 2020 20:22:39 -0400
Subject: [PATCH] Parser: Move disable fork and wait fork down into elaborate
 stage

---
 src/V3AstNodes.h                  | 16 ++++++++++++++++
 src/V3Width.cpp                   |  8 ++++++++
 src/verilog.y                     |  4 ++--
 test_regress/t/t_fork_disable.out | 13 +++++++++++++
 test_regress/t/t_fork_disable.pl  | 20 ++++++++++++++++++++
 test_regress/t/t_fork_disable.v   | 22 ++++++++++++++++++++++
 6 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 test_regress/t/t_fork_disable.out
 create mode 100755 test_regress/t/t_fork_disable.pl
 create mode 100644 test_regress/t/t_fork_disable.v

diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index 2a9f00e65..1fcc89a7c 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -4337,6 +4337,22 @@ public:
     }
 };
 
+class AstDisableFork : public AstNodeStmt {
+    // A "disable fork" statement
+public:
+    AstDisableFork(FileLine* fl)
+        : ASTGEN_SUPER(fl) {}
+    ASTNODE_NODE_FUNCS(DisableFork)
+};
+
+class AstWaitFork : public AstNodeStmt {
+    // A "wait fork" statement
+public:
+    AstWaitFork(FileLine* fl)
+        : ASTGEN_SUPER(fl) {}
+    ASTNODE_NODE_FUNCS(WaitFork)
+};
+
 class AstReturn : public AstNodeStmt {
 public:
     explicit AstReturn(FileLine* fl, AstNode* lhsp = NULL)
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 0172750c1..129f4ec36 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -568,6 +568,14 @@ private:
             // TBD might support only normal join, if so complain about other join flavors
         }
     }
+    virtual void visit(AstDisableFork* nodep) VL_OVERRIDE {
+        nodep->v3warn(E_UNSUPPORTED, "Unsupported: disable fork statements");
+        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+    }
+    virtual void visit(AstWaitFork* nodep) VL_OVERRIDE {
+        nodep->v3warn(E_UNSUPPORTED, "Unsupported: wait fork statements");
+        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+    }
     virtual void visit(AstToLowerN* nodep) VL_OVERRIDE {
         if (m_vup->prelim()) {
             iterateCheckString(nodep, "LHS", nodep->lhsp(), BOTH);
diff --git a/src/verilog.y b/src/verilog.y
index 856fa2978..793911f67 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -3039,7 +3039,7 @@ statement_item<nodep>:		// IEEE: statement_item
 	//
 	//			// IEEE: disable_statement
 	|	yDISABLE idAny/*hierarchical_identifier-task_or_block*/ ';'	{ $$ = new AstDisable($1,*$2); }
-	|	yDISABLE yFORK ';'			{ $$ = NULL; BBUNSUP($1, "Unsupported: disable fork statements"); }
+	|	yDISABLE yFORK ';'			{ $$ = new AstDisableFork($1); }
 	//			// IEEE: event_trigger
 	|	yP_MINUSGT idDotted/*hierarchical_identifier-event*/ ';'
 			{ // AssignDly because we don't have stratified queue, and need to
@@ -3080,7 +3080,7 @@ statement_item<nodep>:		// IEEE: statement_item
 	//
 	//			// IEEE: wait_statement
 	|	yWAIT '(' expr ')' stmtBlock		{ $$ = NULL; BBUNSUP($1, "Unsupported: wait statements"); }
-	|	yWAIT yFORK ';'				{ $$ = NULL; BBUNSUP($1, "Unsupported: wait fork statements"); }
+	|	yWAIT yFORK ';'				{ $$ = new AstWaitFork($1); }
 	//UNSUP	yWAIT_ORDER '(' hierarchical_identifierList ')' action_block	{ UNSUP }
 	//
 	//			// IEEE: procedural_assertion_statement
diff --git a/test_regress/t/t_fork_disable.out b/test_regress/t/t_fork_disable.out
new file mode 100644
index 000000000..20a700eb3
--- /dev/null
+++ b/test_regress/t/t_fork_disable.out
@@ -0,0 +1,13 @@
+%Error-UNSUPPORTED: t/t_fork_disable.v:12:7: Unsupported: fork statements
+                                           : ... In instance t
+   12 |       fork
+      |       ^~~~
+%Error-UNSUPPORTED: t/t_fork_disable.v:16:7: Unsupported: disable fork statements
+                                           : ... In instance t
+   16 |       disable fork;
+      |       ^~~~~~~
+%Error-UNSUPPORTED: t/t_fork_disable.v:17:7: Unsupported: wait fork statements
+                                           : ... In instance t
+   17 |       wait fork;
+      |       ^~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_fork_disable.pl b/test_regress/t/t_fork_disable.pl
new file mode 100755
index 000000000..89ffd046b
--- /dev/null
+++ b/test_regress/t/t_fork_disable.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::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
+# 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(linter => 1);
+
+lint(
+    verilator_flags2 => ['--lint-only'],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_fork_disable.v b/test_regress/t/t_fork_disable.v
new file mode 100644
index 000000000..f404a53c2
--- /dev/null
+++ b/test_regress/t/t_fork_disable.v
@@ -0,0 +1,22 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+
+   logic never;
+
+   initial begin
+      fork
+         #10;
+         #10;
+      join_none
+      disable fork;
+      wait fork;
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule