Explicitly size all parameters, even if not used for module cells

src/V3Const.cpp

@@ -1713,7 +1713,14 @@ void V3Const::constifyParam(AstNode* nodep) {
 	V3Signed::signedParams(nodep);
     }
     ConstVisitor visitor (true,false,false,false);
-    visitor.main(nodep);
+    if (AstVar* varp=nodep->castVar()) {
+	// If a var wants to be constified, it's really a param, and
+	// we want the value to be constant.  We aren't passed just the
+	// init value because we need widthing above to handle the var's type.
+	if (varp->initp()) visitor.main(varp->initp());
+    } else {
+	visitor.main(nodep);
+    }
     // Because we do edits, nodep links may get trashed and core dump this.
     //if (debug()>0) nodep->dumpTree(cout,"  forceConDONE: ");
 }

src/V3Param.cpp

@@ -127,6 +127,14 @@ private:
     }
     virtual void visit(AstCell* nodep, AstNUser*);
 
+    // Make sure all parameters are constantified
+    virtual void visit(AstVar* nodep, AstNUser*) {
+	if (nodep->isParam()) {
+	    if (!nodep->hasSimpleInit()) { nodep->v3fatalSrc("Parameter without initial value"); }
+	    V3Const::constifyParam(nodep);  // The variable, not just the var->init()
+	}
+    }
+
     // Generate Statements
     virtual void visit(AstGenerate* nodep, AstNUser*) {
 	if (debug()>=9) nodep->dumpTree(cout,"-genin: ");

src/V3Width.cpp

@@ -442,6 +442,8 @@ private:
     virtual void visit(AstVar* nodep, AstNUser* vup) {
 	//if (debug()) nodep->dumpTree(cout,"  InitPre: ");
 	// Must have deterministic constant width
+	// We can't skip this step when width()!=0, as creating a AstVar
+	// with non-constant range gets size 1, not size 0.
 	int width=1; int mwidth=1;
 	nodep->arraysp()->iterateAndNext(*this,WidthVP(ANYSIZE,0,BOTH).p());
 	if (nodep->rangep()) {
@@ -457,8 +459,11 @@ private:
 	}
 	if (nodep->initp()) {
 	    nodep->initp()->iterateAndNext(*this,WidthVP(width,0,BOTH).p());
-	    if (nodep->isParam() && !nodep->rangep()) {
-		if (nodep->initp()->widthSized()) {
+	    if (nodep->isParam()) {
+		if (nodep->rangep()) {
+		    // Parameters need to preserve widthMin from the value, not get a constant size
+		    mwidth = nodep->initp()->widthMin();
+		} else if (nodep->initp()->widthSized()) {
 		    width = mwidth = nodep->initp()->width();
 		} else {
 		    if (nodep->initp()->width()>32) nodep->initp()->v3warn(WIDTH,"Assigning >32 bit to unranged parameter (defaults to 32 bits)\n");
@@ -847,7 +852,7 @@ public:
 	m_taskDepth = 0;
 	m_cellRangep = NULL;
 	m_casep = NULL;
-	nodep->accept(*this);
+	nodep->accept(*this, WidthVP(ANYSIZE,0,BOTH).p());
     }
     virtual ~WidthVisitor() {}
 };

test_regress/t/t_func_const_bad.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# 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
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+	 v_flags2 => ["--lint-only"],
+	 fails=>1,
+	 expect=>
+q{%Error: t/t_func_const_bad.v:\d+: Expecting expression to be constant, but can't convert a FUNCREF 'f_bad_output' to constant.
+%Error: t/t_func_const_bad.v:\d+: Expecting expression to be constant, but can't convert a FUNCREF 'f_bad_dotted' to constant.
+%Error: t/t_func_const_bad.v:\d+: Expecting expression to be constant, but can't convert a FUNCREF 'f_bad_nonparam' to constant.
+%Error: Exiting due to.*},
+	 );
+
+ok(1);
+1;

test_regress/t/t_func_const_bad.v

@@ -0,0 +1,28 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2009 by Wilson Snyder.
+
+module t;
+
+   // Speced ignored: system calls.  I think this is nasty, so we error instead.
+   // Speced Illegal: inout/output/ref not allowed
+   localparam B1 = f_bad_output(1,2);
+   function integer f_bad_output(input [31:0] a, output [31:0] o);
+      f_bad_output = 0;
+   endfunction
+   // Speced Illegal: void
+   // Speced Illegal: dotted 
+   localparam EIGHT = 8;
+   localparam B2 = f_bad_dotted(2);
+   function integer f_bad_dotted(input [31:0] a);
+      f_bad_dotted = t.EIGHT;
+   endfunction
+   // Speced Illegal: ref to non-local var
+   integer modvar;
+   localparam B3 = f_bad_nonparam(3);
+   function integer f_bad_nonparam(input [31:0] a);
+      f_bad_nonparam = modvar;
+   endfunction
+   // Speced Illegal: needs constant function itself
+endmodule

test_regress/t/t_param.v

@@ -36,8 +36,10 @@ module t (/*AUTOARG*/
 endmodule
 
 module m1;
+   localparam PAR1MINUS1 = PAR1DUP-2-1;
+   localparam PAR1DUP = PAR1+2;  // Check we propagate parameters properly
    parameter PAR1 = 0;
-   m2 #(PAR1-1) m2 ();
+   m2 #(PAR1MINUS1) m2 ();
 endmodule
 
 module m2;