Add PINNOTFOUND warning in place of "Pin not found" error (#2868)

bin/verilator

@@ -4740,6 +4740,34 @@ Warns that an instance has a pin which is not connected to another signal.
 Disabled by default as this is a code style warning; it will simulate
 correctly.
 
+=item PINNOTFOUND
+
+Warns that an instance port or Parameter was not found in the module being
+instanciated. Please note that Verilator raises these errors also on instances
+that should be disabled by generate/if/endgenerate constructs:
+
+    module a;
+      localparam A=1;
+      generate
+         if (A==0) begin
+            b b_inst1 (.x(1'b0)); // nonexistent port
+            b #(.PX(1'b0)) b_inst2 (); // nonexistent parameter
+         end
+       endgenerate
+    endmodule
+
+    module b;
+    endmodule
+
+In the example above, b is instantiated with a port named x, but module b has
+no such port. In the next line, b is instantiated again with
+a nonexistent parameter PX. Technically, this code is incorrect because of
+this, but other tools may ignore it because module b is not instantiated
+due to the generate/if condition being false.
+
+It is possible to disable the error above using:
+/* verilator lint_off PINNOTFOUND */
+
 =item PKGNODECL
 
 Error that a package/class appears to have been referenced that has not yet

docs/CONTRIBUTORS

@@ -82,6 +82,7 @@ Tobias Wölfel
 Todd Strader
 Tomasz Gorochowik
 Tymoteusz Blazejczyk
+Udi Finkelstein
 Unai Martinez-Corral
 Vassilis Papaefstathiou
 Veripool API Bot

src/V3Error.h

@@ -101,9 +101,10 @@ public:
         MULTIDRIVEN,    // Driven from multiple blocks
         MULTITOP,       // Multiple top level modules
         NOLATCH,        // No latch detected in always_latch block
+        PINCONNECTEMPTY,// Cell pin connected by name with empty reference
         PINMISSING,     // Cell pin not specified
         PINNOCONNECT,   // Cell pin not connected
-        PINCONNECTEMPTY,// Cell pin connected by name with empty reference
+        PINNOTFOUND,    // instance port name not found in it's module
         PKGNODECL,      // Error: Package/class needs to be predeclared
         PROCASSWIRE,    // Procedural assignment on wire
         RANDC,          // Unsupported: 'randc' converted to 'rand'
@@ -166,8 +167,8 @@ public:
             "IMPERFECTSCH", "IMPLICIT", "IMPORTSTAR", "IMPURE",
             "INCABSPATH", "INFINITELOOP", "INITIALDLY", "INSECURE",
             "LATCH", "LITENDIAN", "MODDUP",
-            "MULTIDRIVEN", "MULTITOP","NOLATCH",
-            "PINMISSING", "PINNOCONNECT", "PINCONNECTEMPTY", "PKGNODECL", "PROCASSWIRE",
+            "MULTIDRIVEN", "MULTITOP","NOLATCH", "PINCONNECTEMPTY", 
+            "PINMISSING", "PINNOCONNECT",  "PINNOTFOUND", "PKGNODECL", "PROCASSWIRE",
             "RANDC", "REALCVT", "REDEFMACRO",
             "SELRANGE", "SHORTREAL", "SPLITVAR", "STMTDLY", "SYMRSVDWORD", "SYNCASYNCNET",
             "TICKCOUNT", "TIMESCALEMOD",
@@ -190,7 +191,8 @@ public:
     // Later -Werror- options may make more of these.
     bool pretendError() const {
         return (m_e == ASSIGNIN || m_e == BLKANDNBLK || m_e == BLKLOOPINIT || m_e == CONTASSREG
-                || m_e == IMPURE || m_e == PKGNODECL || m_e == PROCASSWIRE);  // Says IEEE
+                || m_e == IMPURE || m_e == PINNOTFOUND || m_e == PKGNODECL
+                || m_e == PROCASSWIRE);  // Says IEEE
     }
     // Warnings to mention manual
     bool mentionManual() const {

src/V3LinkDot.cpp

@@ -2023,9 +2023,10 @@ private:
                                                                  LinkNodeMatcherVarParam())
                                       : m_statep->suggestSymFlat(m_pinSymp, nodep->name(),
                                                                  LinkNodeMatcherVarIO()));
-                nodep->v3error(ucfirst(whatp)
-                               << " not found: " << nodep->prettyNameQ() << '\n'
-                               << (suggest.empty() ? "" : nodep->warnMore() + suggest));
+                nodep->v3warn(PINNOTFOUND,
+                              ucfirst(whatp)
+                                  << " not found: " << nodep->prettyNameQ() << '\n'
+                                  << (suggest.empty() ? "" : nodep->warnMore() + suggest));
             } else if (AstVar* refp = VN_CAST(foundp->nodep(), Var)) {
                 if (!refp->isIO() && !refp->isParam() && !refp->isIfaceRef()) {
                     nodep->v3error(ucfirst(whatp) << " is not an in/out/inout/param/interface: "

test_regress/t/t_class_param_bad.out

@@ -1,8 +1,8 @@
-%Error: t/t_class_param_bad.v:12:11: Parameter pin not found: 'PARAMBAD'
-                                   : ... Suggested alternative: 'PARAMB'
+%Error-PINNOTFOUND: t/t_class_param_bad.v:12:11: Parameter pin not found: 'PARAMBAD'
+                                               : ... Suggested alternative: 'PARAMB'
    12 |    Cls #(.PARAMBAD(1)) c;   
       |           ^~~~~~~~
-%Error: t/t_class_param_bad.v:13:14: Parameter pin not found: '__paramNumber2'
+%Error-PINNOTFOUND: t/t_class_param_bad.v:13:14: Parameter pin not found: '__paramNumber2'
    13 |    Cls #(13, 1) cd;   
       |              ^
 %Error: Exiting due to

test_regress/t/t_lint_pindup_bad.out

@@ -8,12 +8,12 @@
         t/t_lint_pindup_bad.v:20:10: ... Location of original pin connection
    20 |         .i(i),
       |          ^
-%Error: t/t_lint_pindup_bad.v:22:10: Pin not found: 'nexist'
-                                   : ... Suggested alternative: 'exists'
+%Error-PINNOTFOUND: t/t_lint_pindup_bad.v:22:10: Pin not found: 'nexist'
+                                               : ... Suggested alternative: 'exists'
    22 |         .nexist(i2)   
       |          ^~~~~~
-%Error: t/t_lint_pindup_bad.v:16:9: Parameter pin not found: 'NEXIST'
-                                  : ... Suggested alternative: 'EXIST'
+%Error-PINNOTFOUND: t/t_lint_pindup_bad.v:16:9: Parameter pin not found: 'NEXIST'
+                                              : ... Suggested alternative: 'EXIST'
    16 |        .NEXIST(1),   
       |         ^~~~~~
 %Error: t/t_lint_pindup_bad.v:17:9: Duplicate parameter pin connection: 'P'

test_regress/t/t_lint_pinnotfound.pl

@@ -0,0 +1,13 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+lint(
+    );
+
+ok(1);
+1;

test_regress/t/t_lint_pinnotfound.v

@@ -0,0 +1,20 @@
+// 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
+
+/* verilator lint_off PINNOTFOUND */
+module a;
+localparam A=1;
+generate
+if (A==0)
+begin
+b b_inst1 (.x(1'b0)); // nonexistent port
+b #(.PX(1'b0)) b_inst2 (); // nonexistent parameter
+end
+endgenerate
+endmodule
+
+module b;
+endmodule

test_regress/t/t_lint_pinnotfound_bad.out

@@ -0,0 +1,7 @@
+%Error-PINNOTFOUND: t/t_lint_pinnotfound_bad.v:12:13: Pin not found: 'x'
+   12 | b b_inst1 (.x(1'b0));  
+      |             ^
+%Error-PINNOTFOUND: t/t_lint_pinnotfound_bad.v:13:6: Parameter pin not found: 'PX'
+   13 | b #(.PX(1'b0)) b_inst2 ();  
+      |      ^~
+%Error: Exiting due to

test_regress/t/t_lint_pinnotfound_bad.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/env 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.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_lint_pinnotfound_bad.v

@@ -0,0 +1,19 @@
+// 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 a;
+localparam A=1;
+generate
+if (A==0)
+begin
+b b_inst1 (.x(1'b0)); // nonexistent port
+b #(.PX(1'b0)) b_inst2 (); // nonexistent parameter
+end
+endgenerate
+endmodule
+
+module b;
+endmodule