Read-only release history for Verilog-Perl
Perl Bison C++ Verilog Coq SystemVerilog
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.



    Verilog-Perl - Overview of Verilog language packages for Perl


    The Verilog-Perl distribution provides Perl parsing and utilities for
    the Verilog Language. This file provides an overview of the
    distribution, for specific details on each component, see that
    component's manpage.

    You may also want to try the AUTO features present in
    <> Verilog-Mode.


    Skip this section if Verilog-Perl has already been installed.

  Supported Systems

    Verilog-Perl should run on any system with Perl, G++, Flex, and Bison.
    It is known to work on at least:

    *   sparc-sun-solaris2.5.1

    *   i386-linux

    *   i686-w2k-cygwin

  CPAN Installation

        Easiest installation is using the "CPAN" command line that comes
        with Perl. After configuring CPAN the first time, simply

           $ cpan
           cpan> install Verilog-Perl

        Read the rest of this file for details on the programs provided.

  Manual Installation

        Download the latest version from <>, or
        from <>.

        "cd" to the directory containing this README notice.

        Type "perl Makefile.PL" to configure Verilog for your system.

        Type "make" to compile Verilog. Some Solaris users have had trouble
        with "open" being redefined. If this happens, try editing the
        Makefile to change _FILE_OFFSET_BITS to 32 instead of 64.

        Type "make test" to check the package. If you don't have Synopsys'
        VCS, the test will print a warning, which you can ignore.

        Type "make install" to install the programs and any data files and

        Read the rest of this file for details on the programs provided.


    The following scripts are installed by Verilog-Perl:

        Vhier reads the Verilog files passed on the command line and outputs
        a tree of all of the filenames, modules, and cells referenced by
        that file.

        Vpassert will read the specified Verilog files and preprocess
        special PLI assertions.

        Vppreproc (Verilog-Perl Pre Processor) reads the Verilog files
        passed on the command line and outputs preprocessed output.

        Vrename will allow a signal to be changed across all levels of the
        design hierarchy, or to create a cross reference of signal names.


        Verilog::Getopt provides standardized handling of options similar to
        Verilog/VCS and cc/GCC.

        Verilog::Language provides general utilities for using the Verilog
        Language, such as parsing numbers or determining what keywords

        Verilog::Netlist reads and holds interconnect information about a
        whole design database.

        A Verilog::Netlist::Cell object is created by Verilog::Netlist for
        every instantiation in the current module.

        A Verilog::Netlist::ContAssign object is created by Verilog::Netlist
        for every continuous assignment in the current module.

        Verilog::Netlist::File allows Verilog::Netlist objects to be read
        and written in Verilog format.

        A Verilog::Netlist::Module object is created by Verilog::Netlist for
        every module in the design.

        A Verilog::Netlist::Net object is created by
        Verilog::Netlist::Module for every signal and input/output
        declaration in the current module.

        A Verilog::Netlist::Pin object is created by Verilog::Netlist::Cell
        for for each pin connection on a cell.

        A Verilog::Netlist::Port object is created by
        Verilog::Netlist::Module for every port connection in the module.

        The Verilog::Netlist::Subclass is used as a base class for all
        Verilog::Netlist::* structures.

        Verilog::Parser will tokenize a Verilog file and invoke various
        callback methods.

        Verilog::Preproc reads Verilog files, and preprocesses them
        according to the Verilog specification. Programs can be easily
        converted from reading a IO::File into reading preprocessed output
        from Verilog::Preproc.

        Verilog::SigParser builds upon the Verilog::Parser package to
        provide callbacks for when a signal is declared, a module
        instantiated, or a module defined.


    If you are starting a new application which needs to parse the Verilog
    language you have several tools available to you. Which you pick depends
    on how low level and complete the information you need is.

        The low level VParse* source files may be of use when you need a
        starting point for your own a full C++ SystemVerilog grammar parser,
        using Bison and Flex. It understands most of the SystemVerilog 2012
        grammar (1800-2012 Appendix A).

        Verilog::Preproc is useful when you need only post-preprocessed text
        output, or a list of defines, includes, etc. It can preprocess a
        file, or be used to provide the Verilog macro language on top of
        synthesis scripts. It understands and implements all preprocessor
        features of SystemVerilog 2012.

        Verilog::Parser is useful when you need to tokenize or write source
        filters (where you need everything including whitespace). It can
        take raw files, or preprocessed input, and generates callbacks. It
        understands all SystemVerilog 2012 keywords.

    Abstract Syntax Tree
        Verilog::Parser knows enough to make a complete Abstract Syntax Tree
        (AST) of Verilog syntax. This represents all major constructs such
        as a "module" as a data structure, but does not interconnect the AST
        nodes as would be needed to follow signals. Not all keywords have
        been implemented; many are parsed but otherwise ignored. A complete
        Ast tree would allow any arbitrary transformation of Verilog syntax
        (everything is known excluding whitespace). If you'd find this
        useful please contact the author.

        Verilog::SigParser is useful when you need a list of modules,
        signals, ports, functions, etc. It requires a preprocessed file
        (from Verilog::Preproc), and can parse all SystemVerilog 2012 files,
        but only provides callbacks on certain interesting things. The
        SigParser operates only on a file at a time; it does not
        interconnect signals nor perform any elaboration (resolution of

        Verilog::Netlist is useful for when you need the hierarchy, and a
        list of signals per module, pins per cell, etc. It builds upon the
        output of Verilog::SigParser, so requires preprocessed files (from
        Verilog::Preproc). It parses all SystemVerilog 2012 files, but not
        all SystemVerilog constructs are loaded into objects.
        Verilog::Netlist interconnects modules with instantiations but does
        not perform any elaboration (resolution of parameters).

        This is probably the most popular choice.

    VPI Using the VPI is the best way to access the behavior of the design.
        It is not part of this package as it requires a compliant simulator
        and C++ code to call the VPI, and understands as much of the
        language as the simulator supports. This allows writing lint checks
        and full knowledge of all parts of the code. The VPI can operate
        ONLY on an elaborated design (where all parameters are resolved).
        Walking a VPI tree general requires a good deal of work compared to
        simple scripting (though little work compared to writing a parser
        from scratch).

        The Verilator program also contains a very similar front end as
        Verilog-Perl. It also understands how to elaborate and connect
        complex pins and types, but supports mostly the synthesis subset. If
        you're looking to add some lint like checks against netlists, this
        may be a better starting point.

    Verilog-Mode for Emacs
        Although not a parser, a common requested use of Verilog-Perl is to
        automatically make shell modules and interconnect modules.
        Verilog-Mode is a better solution to this problem, as it results in
        completely portable code; the program (Verilog-Mode) isn't needed
        for others to update the design. It's also in very common usage,
        including by many IP providers.


    Why do I get "unexpected `do'" or "unexpected `bit'" errors?
        Do, bit, ref, return, and other words are now SystemVerilog
        keywords. You should change your code to not use them to insure it
        works with newer tools. Alternatively, surround them by the Verilog
        2005/SystemVerilog begin_keywords pragma to indicate Verilog 2001

           `begin_keywords "1364-2001"
              integer bit; initial bit = 1;

        Alternatively use the --language (for vhier) or
        Verilog::Language::language_standard call to specify "1364-2001", or
        for really old code, "1364-1995".

        But, again, you really should fix the Verilog code.

    With Verilog::Netlist how do I resolve signal widths that include
    parameters down to constants?
        Unfortunately parameter resolution is part of elaboration.
        Verilog-Perl doesn't do elaboration as it requires a good fraction
        of a complete simulator implementation. Many applications can work
        around this limitation, if yours still requires elaboration you're
        stuck with using Verilator or the VPI, see the sections above.


    Verilog-Perl is part of the <> free Verilog EDA
    software tool suite. The latest version is available from CPAN and from

    Copyright 2000-2014 by Wilson Snyder. This package 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.

    This code is provided with no warranty of any kind, and is used entirely
    at your own risk.


    Wilson Snyder <>


    vhier, vpassert, vppreproc, vrename

    Verilog::EditFiles, Verilog::Getopt, Verilog::Language Verilog::Netlist,
    Verilog::Parser, Verilog::Preproc, Verilog::SigParser

    Verilog::Netlist::Cell, Verilog::Netlist::ContAssign,
    Verilog::Netlist::File, Verilog::Netlist::Interface,
    Verilog::Netlist::ModPort, Verilog::Netlist::Module,
    Verilog::Netlist::Net, Verilog::Netlist::Pin, Verilog::Netlist::Port,

    And the <>Verilog-Mode package for