From 0de2dcb211efece6f78ba279827cdc5957367b0a Mon Sep 17 00:00:00 2001
From: Stephen Williams <steve@icarus.com>
Date: Sun, 17 Aug 2008 08:22:42 -0700
Subject: [PATCH] Allow elaborate_expr to handle implicit nets.

When the elaborate_expr code is used for expressions of continuous
assignments, it needs to be able to create implicit nets.
---
 elab_expr.cc | 16 ++++++++++++++++
 elaborate.cc |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/elab_expr.cc b/elab_expr.cc
index fd033ab33..76d966130 100644
--- a/elab_expr.cc
+++ b/elab_expr.cc
@@ -1078,6 +1078,22 @@ NetExpr* PEIdent::elaborate_expr(Design*des, NetScope*scope,
 	    }
       }
 
+      if (error_implicit==false
+	  && sys_task_arg==false
+	  && path_.size()==1
+	  && scope->default_nettype() != NetNet::NONE) {
+	    NetNet::Type nettype = scope->default_nettype();
+	    net = new NetNet(scope, peek_tail_name(path_), nettype, 1);
+	    net->data_type(IVL_VT_LOGIC);
+	    net->set_line(*this);
+	    if (warn_implicit) {
+		  cerr << get_fileline() << ": warning: implicit "
+			"definition of wire " << scope_path(scope)
+		       << "." << peek_tail_name(path_) << "." << endl;
+	    }
+	    return elaborate_expr_net(des, scope, net, scope, sys_task_arg);
+      }
+
 	// At this point we've exhausted all the possibilities that
 	// are not scopes. If this is not a system task argument, then
 	// it cannot be a scope name, so give up.
diff --git a/elaborate.cc b/elaborate.cc
index 9254a889c..213f66443 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -3494,6 +3494,7 @@ static void elaborate_tasks(Design*des, NetScope*scope,
 bool Module::elaborate(Design*des, NetScope*scope) const
 {
       bool result_flag = true;
+      error_implicit = true;
 
       if (gn_specify_blocks_flag) {
 	      // Elaborate specparams
@@ -3558,6 +3559,7 @@ bool Module::elaborate(Design*des, NetScope*scope) const
 	// complex.
       const list<PGate*>&gl = get_gates();
 
+      error_implicit = false;
       for (list<PGate*>::const_iterator gt = gl.begin()
 		 ; gt != gl.end()
 		 ; gt ++ ) {
@@ -3565,6 +3567,8 @@ bool Module::elaborate(Design*des, NetScope*scope) const
 	    (*gt)->elaborate(des, scope);
       }
 
+      error_implicit = true;
+
 	// Elaborate the behaviors, making processes out of them. This
 	// involves scanning the PProcess* list, creating a NetProcTop
 	// for each process.