Add recursive define detection, bug1574.

Changes

@@ -25,7 +25,7 @@ The contributors that suggested a given feature are shown in []. Thanks!
 ****  Fix multithreaded yield behavior when no work.  [Patrick Stewart]
 
 ****  Fix bad-syntax crashes, bug1548, bug1550-1553, bug1557-1560, bug1563,
-      bug1573. [Eric Rippey]
+      bug1573, bug1574. [Eric Rippey]
 
 ****  Benchmark --protect-lib runtime, bug1519. [Todd Strader]
 

src/V3PreProc.cpp

@@ -118,6 +118,8 @@ public:
     V3PreProc* m_preprocp;  ///< Object we're holding data for
     V3PreLex* m_lexp;  ///< Current lexer state (NULL = closed)
     std::stack<V3PreLex*> m_includeStack;  ///< Stack of includers above current m_lexp
+    int m_lastLineno;  // Last line number (stall detection)
+    int m_tokensOnLine;  // Number of tokens on line (stall detection)
 
     enum ProcState { ps_TOP,
                      ps_DEFNAME_UNDEF, ps_DEFNAME_DEFINE,
@@ -266,6 +268,8 @@ public:
         m_finFilelinep = NULL;
         m_lexp = NULL;
         m_preprocp = NULL;
+        m_lastLineno = 0;
+        m_tokensOnLine = 0;
     }
     void configure(FileLine* filelinep) {
         // configure() separate from constructor to avoid calling abstract functions
@@ -889,6 +893,15 @@ int V3PreProcImp::getRawToken() {
         int tok = m_lexp->lex();
         if (debug()>=5) debugToken(tok, "RAW");
 
+        if (m_lastLineno != m_lexp->m_tokFilelinep->lineno()) {
+            m_lastLineno = m_lexp->m_tokFilelinep->lineno();
+            m_tokensOnLine = 0;
+        } else if (++m_tokensOnLine > LINE_TOKEN_MAX) {
+            error("Too many preprocessor tokens on a line (>"+cvtToStr(LINE_TOKEN_MAX)
+                  +"); perhaps recursive `define");
+            tok = VP_EOF_ERROR;
+        }
+
         if (tok==VP_EOF || tok==VP_EOF_ERROR) {
             // An error might be in an unexpected point, so stop parsing
             if (tok==VP_EOF_ERROR) forceEof();

src/V3PreProc.h

@@ -49,6 +49,7 @@ public:
     // CONSTANTS
     enum MiscConsts {
         DEFINE_RECURSION_LEVEL_MAX = 1000,      // How many `def substitutions before an error
+        LINE_TOKEN_MAX = 20000,                 // How many tokens on a line before an error
         INCLUDE_DEPTH_MAX = 500,                // How many `includes deep before an error
         STREAM_DEPTH_LEVEL_MAX = 2000,          // How many streams deep (sometimes `def deep) before an error
         //                                      // Set more than DEFINE_RECURSION_LEVEL_MAX

test_regress/t/t_pp_circ_subst_bad.out

@@ -0,0 +1,3 @@
+%Error: t/t_pp_circ_subst_bad.v:7: Too many preprocessor tokens on a line (>20000); perhaps recursive `define
+%Error: t/t_pp_circ_subst_bad.v:7: syntax error, unexpected IDENTIFIER
+%Error: Exiting due to

test_regress/t/t_pp_circ_subst_bad.pl

@@ -0,0 +1,18 @@
+#!/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.
+
+scenarios(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_pp_circ_subst_bad.v

@@ -0,0 +1,7 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Wilson Snyder.
+
+`define e fun `e
+`e