Add --coverage-max-width (#2853).

Changes

@@ -17,6 +17,7 @@ Verilator 4.201 devel
 * Changed TIMESCALEMOD from error into a warning.
 * Verilated signals now use VlWide and VlPacked in place of C arrays.
 * Mark --no-relative-cfuncs as scheduled for deprecation.
+* Add --coverage-max-width (#2853). [xuejiazidi]
 * Add VerilatedCovContext::forcePerInstance (#2793). [Kevin Laeufer]
 * Fix class unpacked-array compile error (#2774). [Iru Cai]
 * Fix exceeding command-line ar limit (#2834). [Yinan Xu]

bin/verilator

@@ -313,6 +313,7 @@ arguments.
     --converge-limit <loops>    Tune convergence settle time
     --coverage                  Enable all coverage
     --coverage-line             Enable line coverage
+    --coverage-max-width <width>   Maximum array depth for coverage
     --coverage-toggle           Enable toggle coverage
     --coverage-user             Enable SVL user coverage
     --coverage-underscore       Enable coverage of _signals
@@ -697,6 +698,12 @@ Note Verilator may over-count combinatorial (non-clocked) blocks when those
 blocks receive signals which have had the UNOPTFLAT warning disabled; for
 most accurate results do not disable this warning when using coverage.
 
+=item --trace-max-width I<width>
+
+Rarely needed.  Specify the maximum bit width of a signal that is subject
+to toggle coverage.  Defaults to 256, as covering large vectors may greatly
+slow coverage simulations.
+
 =item --coverage-toggle
 
 Specifies signal toggle coverage analysis code should be inserted.

src/V3Coverage.cpp

@@ -96,8 +96,9 @@ private:
             if (prettyName[0] == '_') return "Leading underscore";
             if (prettyName.find("._") != string::npos) return "Inlined leading underscore";
         }
-        if ((nodep->width() * nodep->dtypep()->arrayUnpackedElements()) > 256) {
-            return "Wide bus/array > 256 bits";
+        if ((nodep->width() * nodep->dtypep()->arrayUnpackedElements())
+            > static_cast<uint32_t>(v3Global.opt.coverageMaxWidth())) {
+            return "Wide bus/array > --coverage-max-width setting's bits";
         }
         // We allow this, though tracing doesn't
         // if (nodep->arrayp(1)) return "Unsupported: Multi-dimensional array";

src/V3Options.cpp

@@ -1237,6 +1237,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
     DECL_OPTION("-coverage", CbOnOff, [this](bool flag) { coverage(flag); });
     DECL_OPTION("-converge-limit", Set, &m_convergeLimit);
     DECL_OPTION("-coverage-line", OnOff, &m_coverageLine);
+    DECL_OPTION("-coverage-max-width", Set, &m_coverageMaxWidth);
     DECL_OPTION("-coverage-toggle", OnOff, &m_coverageToggle);
     DECL_OPTION("-coverage-underscore", OnOff, &m_coverageUnderscore);
     DECL_OPTION("-coverage-user", OnOff, &m_coverageUser);

src/V3Options.h

@@ -283,6 +283,7 @@ private:
 
     int         m_buildJobs = 1;    // main switch: -j
     int         m_convergeLimit = 100;  // main switch: --converge-limit
+    int         m_coverageMaxWidth = 256; // main switch: --coverage-max-width
     int         m_dumpTree = 0;     // main switch: --dump-tree
     int         m_gateStmts = 100;    // main switch: --gate-stmts
     int         m_ifDepth = 0;      // main switch: --if-depth
@@ -477,6 +478,7 @@ public:
 
     int buildJobs() const { return m_buildJobs; }
     int convergeLimit() const { return m_convergeLimit; }
+    int coverageMaxWidth() const { return m_coverageMaxWidth; }
     int dumpTree() const { return m_dumpTree; }
     bool dumpTreeAddrids() const { return m_dumpTreeAddrids; }
     int gateStmts() const { return m_gateStmts; }

test_regress/t/t_cover_toggle.pl

@@ -21,6 +21,8 @@ execute(
 # Read the input .v file and do any CHECK_COVER requests
 inline_checks();
 
+file_grep_not("$Self->{obj_dir}/coverage.dat", "largeish");
+
 file_grep($Self->{stats}, qr/Coverage, Toggle points joined\s+(\d+)/i, 25)
     if $Self->{vlt_all};
 

test_regress/t/t_cover_toggle.v

@@ -62,7 +62,7 @@ module t (/*AUTOARG*/
 
    reg [1:0]  memory[121:110];
 
-   reg [1023:0] largeish;
+   wire [1023:0] largeish = {992'h0, cyc};
    // CHECK_COVER_MISSING(-1)
 
    always @ (posedge clk) begin

test_regress/t/t_cover_toggle_width.pl

@@ -0,0 +1,26 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003-2009 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t/t_cover_toggle.v");
+
+compile(
+    verilator_flags2 => ['--cc --coverage-toggle --coverage-max-width 1025'],
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+file_grep("$Self->{obj_dir}/coverage.dat", "largeish");
+
+ok(1);
+1;