Generate file with waivers (#2354)

This adds the flag --generate-waivefile <filename>. This will generate
a verilator config file with the proper lint_off statemens to turn off
warnings emitted during this particular run.

This feature can be used to start with using Verilator as linter and
systematically capture all known lint warning for further
elimination. It hopefully helps people turning of -Wno-fatal or
-Wno-lint and gradually improve their code base.

Signed-off-by: Stefan Wallentowitz <[email protected]>

src/V3FileLine.cpp

@@ -28,6 +28,7 @@
 # include "V3Config.h"
 # include "V3File.h"
 #endif
+#include "V3Waiver.h"
 // clang-format on
 
 #include <algorithm>
@@ -366,6 +367,7 @@ void FileLine::v3errorEnd(std::ostringstream& sstr, const string& locationStr) {
     } else if (!V3Error::errorContexted()) {
         nsstr << warnContextPrimary();
     }
+    if (!m_waive) { V3Waiver::addEntry(V3Error::errorCode(), filename(), sstr.str()); }
     V3Error::v3errorEnd(nsstr, lstr.str());
 }