From bdeee35669847ae28433320114b422cb8d2cb0e0 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Wed, 26 Apr 2017 18:34:01 -0400
Subject: [PATCH] Add warning on mis-sized literal, bug1156.

---
 Changes                              |  1 +
 src/V3Number.cpp                     | 18 ++++++++++++------
 src/V3Number.h                       |  2 +-
 test_regress/t/t_lint_literal_bad.pl | 20 ++++++++++++++++++++
 test_regress/t/t_lint_literal_bad.v  | 11 +++++++++++
 5 files changed, 45 insertions(+), 7 deletions(-)
 create mode 100755 test_regress/t/t_lint_literal_bad.pl
 create mode 100644 test_regress/t/t_lint_literal_bad.v

diff --git a/Changes b/Changes
index 354eb4e0d..006d757f3 100644
--- a/Changes
+++ b/Changes
@@ -5,6 +5,7 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 * Verilator 3.903 devel
 
+****  Add warning on mis-sized literal, bug1156. [Todd Strader]
 
 
 * Verilator 3.902 2017-04-02
diff --git a/src/V3Number.cpp b/src/V3Number.cpp
index 70ea2315f..f86597a27 100644
--- a/src/V3Number.cpp
+++ b/src/V3Number.cpp
@@ -48,7 +48,7 @@ V3Number::V3Number(VerilogStringLiteral, FileLine* fileline, const string& str)
 	    }
 	}
     }
-    opCleanThis();
+    opCleanThis(true);
 }
 
 V3Number::V3Number (FileLine* fileline, const char* sourcep) {
@@ -254,7 +254,7 @@ V3Number::V3Number (FileLine* fileline, const char* sourcep) {
 	setBit(obit, bitIs(obit-1));
 	obit++;
     }
-    opCleanThis();
+    opCleanThis(true);
 
     //printf("Dump \"%s\"  CP \"%s\"  B '%c' %d W %d\n", sourcep, value_startp, base, width(), m_value[0]);
 }
@@ -1587,10 +1587,16 @@ V3Number& V3Number::opClean (const V3Number& lhs, uint32_t bits) {
     return opSel(lhs, bits-1, 0);
 }
 
-void V3Number::opCleanThis() {
-    // Clean in place number
-    m_value[words()-1]  &= hiWordMask();
-    m_valueX[words()-1] &= hiWordMask();
+void V3Number::opCleanThis(bool warnOnTruncation) {
+    // Clean MSB of number
+    uint32_t newValueMsb = m_value[words()-1]  & hiWordMask();
+    uint32_t newValueXMsb = m_valueX[words()-1] & hiWordMask();
+    if (warnOnTruncation && (newValueMsb != m_value[words()-1] || newValueXMsb != m_valueX[words()-1])) {
+	// Displaying in decimal avoids hiWordMask truncation
+	m_fileline->v3warn(WIDTH,"Value too large for "<<width()<<" bit number: "<<displayed(m_fileline, "%d"));
+    }
+    m_value[words()-1]  = newValueMsb;
+    m_valueX[words()-1] = newValueXMsb;
 }
 
 V3Number& V3Number::opSel (const V3Number& lhs, const V3Number& msb, const V3Number& lsb) {
diff --git a/src/V3Number.h b/src/V3Number.h
index d2dece53a..88d7b7097 100644
--- a/src/V3Number.h
+++ b/src/V3Number.h
@@ -45,7 +45,7 @@ class V3Number {
     // METHODS
     V3Number& setSingleBits(char value);
     V3Number& setString(const string& str) { m_isString=true; m_stringVal=str; return *this; }
-    void opCleanThis();
+    void opCleanThis(bool warnOnTruncation = false);
 public:
     FileLine*	fileline() const { return m_fileline; }
     void	fileline(FileLine* fl) { m_fileline=fl; }
diff --git a/test_regress/t/t_lint_literal_bad.pl b/test_regress/t/t_lint_literal_bad.pl
new file mode 100755
index 000000000..68e60534c
--- /dev/null
+++ b/test_regress/t/t_lint_literal_bad.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2017 by Todd Strader. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+$Self->skip("Verilator only test") if !$Self->{vlt};
+
+compile (
+	 fails=>1,
+	 expect=>
+'%Warning-WIDTH: t/t_lint_literal_bad.v:9: Value too large for 8 bit number: 256
+',
+	 );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_lint_literal_bad.v b/test_regress/t/t_lint_literal_bad.v
new file mode 100644
index 000000000..521bd10ef
--- /dev/null
+++ b/test_regress/t/t_lint_literal_bad.v
@@ -0,0 +1,11 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2017 by Todd Strader.
+
+module t (
+);
+
+    localparam the_localparam = 8'd256;
+
+endmodule