NAME

Verilog::SigParser - Signal Parsing for Verilog language files

SYNOPSIS

  use Verilog::Preproc;
  use Verilog::SigParser;
  my $pp = Verilog::Preproc->new(keep_comments=>0,);
  my $parser = new Verilog::SigParser;
  $parser->parse_preproc_file($pp);
  # The below described callbacks are then invoked

DESCRIPTION

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

See the "Which Package" section of Verilog::Language if you are unsure which parsing package to use for a new application. For a higher level interface to this package, see Verilog::Netlist.

METHODS

The method interface to Verilog::SigParser is described in the Verilog::Parser module which this package inherits. You will probably want to use the preprocessing option of Verilog::Parser with this package.

CALLBACKS

In order to make the parser do anything interesting, you must make a subclass where you override one or more of the following methods as appropriate.

Note Verilog::Parser callbacks also are invoked when SigParser is parsing.

$self->attribute($text)

Scanned an attribute or meta-comment. The parser inspects the first word of each comment line ("//key rest" to end of line) or comment block ("/*key rest */). It calls "$self-"attribute( meta_text )" if the first word has a true value in hash "$self-"metacomment>.

$self->class($token, $name, $virtual)

This method is called at a class.

$self->covergroup($token, $name)

This method is called at a covergroup.

$self->contassign($token, $lhs, $rhs)

This method is called at a continuous "assign" keyword, with the left and right hand part of the assignment. Note that "wire" initializations are not considered assignments; those are received via the var callback's value parameter.

$self->defparam($token, $lhs, $rhs)

This method is called at a "defparam" keyword, with the left and right hand part of the assignment.

$self->endcell($token)

This method is called at the end of defining a cell. It is useful for writing clean up routines.

$self->endgroup($token)

This method is called at the end of defining a covergroup. It is useful for writing clean up routines.

$self->endinterface($token)

This method is called at a endinterface keyword. It is useful for writing clean up routines.

$self->endclass($token)

This method is called at a endclass keyword. It is useful for writing clean up routines.

$self->endtaskfunc($token)

This method is called at a endfunction or endtask keyword. It is useful for writing clean up routines.

$self->endmodport($token)

This method is called at a endmodport keyword. It is useful for writing clean up routines.

$self->endmodule($token)

This method is called at a endmodule keyword. It is useful for writing clean up routines.

$self->endpackage($token)

This method is called at a endpackage keyword. It is useful for writing clean up routines.

$self->endprogram($token)

This method is called at a endprogram keyword. It is useful for writing clean up routines.

$self->function($keyword, $name, $data-type)

This method is called when a function is defined. Type is the output size or typename, plus "signed", for example "", "[3:0]", "integer", or "signed [2:0]".

$self->import($package, $id)

This method is called when an import is defined.

$self->instant($module, $cell, $range)

This method is called when a instantiation is defined. The first parameter is the name of the module being instantiated. The second parameter is the name of the cell, which may be "" for primitives. The third is the range if the cell was arrayed.

Prior to version 3.000, the name of the parameters were also included in this callback. This has been replaced with the parampin callback.

$self->interface($keyword, $name)

This method is called when an interface is defined.

$self->modport($keyword, $name)

This method is called when an interface modport is defined.

$self->module($keyword, $name, ignored, $in_celldefine)

This method is called when a module is defined.

$self->package($keyword, $name)

This method is called when a package is defined.

$self->parampin($name, $connection, $index)

This method is called when a parameter is connected to an instantiation, IE the "#(...)" syntax. It is also used for UDP delays (Three calls for "#(delay0,delay1,delay2)"), as the parser does not know if the instantiation is for an UDP versus a module.

$self->pin($name, $connection, $index)

This method is called when a pin on an instant is defined and "use_pinselects" is not set (the default, see pinselects() below. If a pin name was not provided and the connection is by position, name will be '' or undef.

If you do not need the pin nor var nor port callbacks, consider the "$self->new (... use_vars=>0 ...)" option to accelerate parsing.

$self->pinselects($name, $connections, $index)

If "$self->new (... use_pinselects=>1 ...)" is used this function is called instead of "$self->pin (...)". The difference is that the second parameter ("$connections") is a Perl hash that contains all connected nets in the case of concatenations including the MSB and LSB bounds used at these locations.

$self->port($name, $objof, $direction, $data_type, $array, $pinnum)

This method is called when a module port is defined. It may be called twice on a port if the 1995 style is used; the first call is made at the port header, the second call at the input/output declaration.

The first argument $name, is the name of the port. $objof is what the port is an object of ('module', 'function', etc). $direction is the port direction ('input', 'output', 'inout', 'ref', 'const ref', or 'interface'). $data_type is the data type ('reg', 'user_type_t', 'signed [31:0]', etc, or for interfaces the "{interface_id}.{modport_name}"). $array is the arraying of the port ('[1:0][2:0]', '', etc). $pinnum is set to the pin number for ANSI style declarations, and 0 for Verilog 1995 declarations made outside the port list.

If you do not need the pin nor var nor port callbacks, consider the "$self->new (... use_vars=>0 ...)" option to accelerate parsing.

$self->program($keyword, $name)

This method is called when a program is defined.

$self->signal_decl($keyword, $signame, $vector, $mem, $signed, $value)

This method is no longer used, see $self->var.

$self->task($keyword, $name)

This method is called when a task is defined.

$self->var($kwd, $name, $objof, $nettype, $data_type, $array, $value)

This method is called when a variable or net is defined.

The first argument $kwd is how it was declared ('port', 'var', 'genvar', 'parameter', 'localparam', 'typedef') or if applicable a net type ('supply0', 'wire', etc). $name is the name of the variable. $objof is what the variable is an object of ('module', 'function', etc). $nettype is the net type if any was defined ('', 'supply0', 'wire', 'tri', etc). $data_type is the data type ('user_type_t', '[31:0] signed', etc). $array is the arraying of the variable which is the text AFTER the variable name ('[1:0][2:0]', '', etc). $value is what the variable was assigned to ('', or expression).

Note typedefs are included here, because "parameter type" is both a variable and a type declaration.

If you do not need the pin nor var nor port callbacks, consider the "$self->new (... use_vars=>0 ...)" option to accelerate parsing.

Below are some example declarations and the callbacks:

   reg [4:0]  vect = 5'b10100;
   # VAR  'var' 'vect' 'module' '' 'reg [4:0]' '' '5'b10100'
   wire (weak0, weak1) value = pullval;
   # VAR  'net' 'value' 'module' 'wire' '' '' 'pullval'
   reg [1:0] mem [12:2];
   # VAR  'var' 'mem' 'module' '' 'reg [1:0]' '[12:2]' ''
   int n[1:2][1:3] = '{'{0,1,2}, '{3{4}}};
   # verilog/parser_sv.v:121: VAR  'var' 'n' 'module' '' 'int' '[1:2][1:3]' ''{'{0,1,2},'{3}}'
   module ( output logic [SZ-1:0] o_sized );
   # VAR  'port' 'o_sized' 'module' '' 'logic [SZ-1:0]' '' ''
   struct packed signed { bit [7:0] m_b; };
   # VAR  'member' 'm_b' 'struct' '' 'bit [7:0]' '' ''
    

BUGS

This is being distributed as a baseline for future contributions. Don't expect a lot, the Parser is still naive, and there are many awkward cases that aren't covered.

Note the SigParser is focused on extracting signal information. It does NOT extract enough information to derive general interconnect; for example the contents of 'assign' statements are not parsed.

DISTRIBUTION

Verilog-Perl is part of the <https://www.veripool.org/> free Verilog EDA software tool suite. The latest version is available from CPAN and from <https://www.veripool.org/verilog-perl>.

Copyright 2000-2022 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.

AUTHORS

Wilson Snyder <wsnyder@wsnyder.org>

SEE ALSO

Verilog-Perl, Verilog::Parser, Verilog::Language, Verilog::Netlist, Verilog::Getopt