Unsized concatenates now give WIDTHCONCAT warnings.

git-svn-id: file://localhost/svn/verilator/trunk/verilator@1020 77ca24e4-aefa-0310-84f0-b9a241c72d87

Changes

@@ -12,6 +12,10 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ***  Add --top-module option to select between multiple tops. [Stefan Thiede]
 
+***  Unsized concatenates now give WIDTHCONCAT warnings. [Jonathan Kimmitt]
+     Previously they threw fatal errors, which in most cases is correct
+     according to spec, but can be incorrect in presence of parameter values.
+
 **** Ignore delays attached to gate UDPs.  [Stefan Thiede]
 
 **** Fix SystemVerilog parameterized defines with `` expansion,

bin/verilator

@@ -1893,6 +1893,24 @@ The best fix, which clarifies intent and will also make all tools happy is:
 Ignoring this warning will only suppress the lint check, it will simulate
 correctly.
 
+=item WIDTHCONCAT
+
+Warns that based on width rules of Verilog, a concatenate or replication
+has a undeterminate width.  In most cases this violates the Verilog rule
+that widths inside concatenates and replicates must be sized, and should be
+fixed in the code.
+
+    wire [63:0] concat = {1,2};
+
+An example where this is technically legal (though still bad form) is:
+
+    parameter PAR = 1;
+    wire [63:0] concat = {PAR,PAR};
+
+The correct fix is to either size the 1 ("32'h1"), or add the width to the
+parameter definition ("parameter [31:0]"), or add the width to the
+parameter usage ("{PAR[31:0],PAR[31:0]}".
+
 =back
 
 The following describes the less obvious errors:

src/V3Error.h

@@ -61,6 +61,7 @@ public:
 	UNUSED,		// No receivers
 	VARHIDDEN,	// Hiding variable
 	WIDTH,		// Width mismatch
+	WIDTHCONCAT,	// Unsized numbers/parameters in concatenations
 	MAX
 	// ***Add new elements below also***
     };
@@ -81,7 +82,7 @@ public:
 	    "COMBDLY", "STMTDLY", "GENCLK", "IMPLICIT", "IMPURE",
 	    "MULTIDRIVEN", "REDEFMACRO",
 	    "UNDRIVEN", "UNOPT", "UNOPTFLAT", "UNSIGNED", "UNUSED",
-	    "VARHIDDEN", "WIDTH",
+	    "VARHIDDEN", "WIDTH", "WIDTHCONCAT",
 	    " MAX"
 	};
 	return names[m_e];

src/V3Number.cpp

@@ -698,8 +698,10 @@ V3Number& V3Number::opXnor (const V3Number& lhs, const V3Number& rhs) {
 
 V3Number& V3Number::opConcat (const V3Number& lhs, const V3Number& rhs) {
     setZero();
-    if (!lhs.sized()) m_fileline->v3error("Unsized constants not allowed in concatenations: "<<lhs);
-    if (!rhs.sized()) m_fileline->v3error("Unsized constants not allowed in concatenations: "<<rhs);
+    // See also error in V3Width
+    if (!lhs.sized() || !rhs.sized()) {
+	m_fileline->v3warn(WIDTHCONCAT,"Unsized numbers/parameters not allowed in concatenations.");
+    }
     int obit = 0;
     for(int bit=0; bit<rhs.width(); bit++) {
 	setBit(obit,rhs.bitIs(bit));
@@ -714,7 +716,8 @@ V3Number& V3Number::opConcat (const V3Number& lhs, const V3Number& rhs) {
 
 V3Number& V3Number::opRepl (const V3Number& lhs, const V3Number& rhs) {	// rhs is # of times to replicate
     // Hopefully the using routine has a error check too.
-    if (!lhs.sized()) m_fileline->v3error("Unsized constants not allowed in concatenations: "<<lhs);
+    // See also error in V3Width
+    if (!lhs.sized()) m_fileline->v3warn(WIDTHCONCAT,"Unsized numbers/parameters not allowed in replications.");
     return opRepl(lhs, rhs.asInt());
 }
 

src/V3Width.cpp

@@ -201,7 +201,10 @@ private:
 			 nodep->lhsp()->widthMin() + nodep->rhsp()->widthMin());
 	}
 	if (vup->c()->final()) {
-	    if (!nodep->widthSized()) nodep->v3error("Concat argument must have specific size. (No unsized numbers/parameters).");
+	    if (!nodep->widthSized()) {
+		// See also error in V3Number
+		nodep->v3warn(WIDTHCONCAT,"Unsized numbers/parameters not allowed in concatenations.");
+	    }
 	}
     }
     virtual void visit(AstReplicate* nodep, AstNUser* vup) {
@@ -217,7 +220,10 @@ private:
 			 (nodep->lhsp()->widthMin() * times));
 	}
 	if (vup->c()->final()) {
-	    if (!nodep->widthSized()) nodep->v3error("Replication expression must have specific size.");
+	    if (!nodep->widthSized()) {
+		// See also error in V3Number
+		nodep->v3warn(WIDTHCONCAT,"Unsized numbers/parameters not allowed in replications.");
+	    }
 	}
     }
     virtual void visit(AstRange* nodep, AstNUser* vup) {

test_regress/t/t_param_concat.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("./driver.pl", @ARGV, $0); die; }
+# $Id$
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# General Public License or the Perl Artistic License.
+
+compile (
+	 verilator_flags2 => ["--Wno-WIDTHCONCAT"],
+	 );
+
+execute (
+	 check_finished=>1,
+     );
+
+ok(1);
+1;

test_regress/t/t_param_concat.v

@@ -0,0 +1,28 @@
+// $Id$
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2005 by Wilson Snyder.
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk
+   );
+   input clk;
+
+   parameter	UNSIZED = 10;
+
+   integer cyc=1;
+   always @ (posedge clk) begin
+      cyc <= cyc + 1;
+      if (cyc==1) begin
+	 if ({UNSIZED,UNSIZED+1} != {32'd10, 32'd11}) $stop;
+	 if ({2{UNSIZED}} != {32'd10, 32'd10}) $stop;
+      end
+      if (cyc==9) begin
+	 $write("*-* All Finished *-*\n");
+	 $finish;
+      end
+   end
+
+endmodule

test_regress/t/t_param_concat_bad.pl

@@ -0,0 +1,24 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("./driver.pl", @ARGV, $0); die; }
+# $Id$
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# General Public License or the Perl Artistic License.
+
+top_filename("t/t_param_concat.v");
+
+compile (
+	 fails=>1,
+	 expect=>
+'%Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in concatenations.
+%Warning-WIDTHCONCAT: Use "/\* verilator lint_off WIDTHCONCAT \*/" and lint_on around source to disable this message.
+%Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in replications.
+%Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in concatenations.
+%Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in replications.
+%Error: Exiting due to.*',
+	 );
+
+ok(1);
+1;