VERILATOR(1)          User Contributed Perl Documentation         VERILATOR(1)


NAME
       Verilator - Lint, compile and simulate SystemVerilog code using
       C++/SystemC

SYNOPSIS
           verilator --help
           verilator --version
           verilator --binary -j 0 [options] [source_files.v]... [opt_c_files.cpp/c/cc/a/o/so]
           verilator --cc [options] [source_files.v]... [opt_c_files.cpp/c/cc/a/o/so]
           verilator --sc [options] [source_files.v]... [opt_c_files.cpp/c/cc/a/o/so]
           verilator --lint-only -Wall [source_files.v]...

DESCRIPTION
       The "Verilator" package converts all synthesizable, and many
       behavioral, Verilog and SystemVerilog designs into a C++ or SystemC
       model that after compiling can be executed.  Verilator is not a
       traditional simulator, but a compiler.

       For documentation see <https://verilator.org/verilator_doc.html>.

ARGUMENT SUMMARY
       This is a short summary of the arguments to the "verilator" executable.
       See <https://verilator.org/guide/latest/exe_verilator.html> for the
       detailed descriptions of these arguments.

           <file.v>                    Verilog package, module, and top module filenames
           <file.c/cc/cpp>             Optional C++ files to compile in
           <file.a/o/so>               Optional C++ files to link in

            +1364-1995ext+<ext>        Use Verilog 1995 with file extension <ext>
            +1364-2001ext+<ext>        Use Verilog 2001 with file extension <ext>
            +1364-2005ext+<ext>        Use Verilog 2005 with file extension <ext>
            +1800-2005ext+<ext>        Use SystemVerilog 2005 with file extension <ext>
            +1800-2009ext+<ext>        Use SystemVerilog 2009 with file extension <ext>
            +1800-2012ext+<ext>        Use SystemVerilog 2012 with file extension <ext>
            +1800-2017ext+<ext>        Use SystemVerilog 2017 with file extension <ext>
            +1800-2023ext+<ext>        Use SystemVerilog 2023 with file extension <ext>
           --no-aslr                   Disable address space layout randomization
           --no-assert                 Disable all assertions
           --no-assert-case            Disable unique/unique0/priority-case assertions
           --assert-unroll-limit <iter> Max SVA assertion repetition before erroring
           --autoflush                 Flush streams after all $displays
           --bbox-sys                  Blackbox unknown $system calls
           --bbox-unsup                Blackbox unsupported language features
           --binary                    Build model binary
           --build                     Build model executable/library after Verilation
           --build-dep-bin <filename>  Override build dependency Verilator binary
           --build-jobs <jobs>         Parallelism for --build
           --cc                        Create C++ output
            -CFLAGS <flags>            C++ compiler arguments for makefile
           --compiler <compiler-name>  Tune for specified C++ compiler
           --compiler-include          Include additional header in the precompiled one
           --constraint-array-limit <size>   Maximum array size for constraint array reduction
           --converge-limit <loops>    Tune convergence settle time
           --coverage                  Enable all coverage
           --coverage-expr             Enable expression coverage
           --coverage-expr-max <value>     Maximum permutations allowed for an expression
           --coverage-fsm              Enable FSM state/arc coverage
           --coverage-line             Enable line coverage
           --coverage-max-width <width>   Maximum array depth for coverage
           --coverage-per-instance     Enable per-instance coverage counters
           --coverage-toggle           Enable toggle coverage
           --coverage-underscore       Enable coverage of _signals
           --coverage-user             Enable SVL user coverage
            -D<var>[=<value>]          Set preprocessor define
           --debug                     Enable debugging
           --debug-check               Enable debugging assertions
           --no-debug-leak             Disable leaking memory in --debug mode
           --debugi <level>            Enable debugging at a specified level
           --debugi-<srcfile> <level>  Enable debugging a source file at a level
           --no-decoration             Disable comments and lower spacing level
           --decorations <level>       Set output comment and spacing level
           --default-language <lang>   Default language to parse
            +define+<var>=<value>      Set preprocessor define
           --diagnostics-sarif         Enable SARIF diagnostics output
           --diagnostics-sarif-output <filename>  Set SARIF diagnostics output file
           --dpi-hdr-only              Only produce the DPI header file
           --dump-<srcfile>            Enable dumping everything in source file
           --dump-ast-patterns         Enable dumping Ast pattern statistics
           --dump-defines              Show preprocessor defines with -E
           --dump-dfg                  Enable dumping DfgGraphs to .dot files
           --dump-dfg-patterns         Enable dumping Dfg pattern statistics
           --dump-graph                Enable dumping V3Graphs to .dot files
           --dump-inputs               Enable dumping preprocessed input files
           --dump-tree                 Enable dumping Ast .tree files
           --dump-tree-addrids         Use short identifiers instead of addresses
           --dump-tree-dot             Enable dumping Ast .tree.dot debug files
           --dump-tree-json            Enable dumping Ast .tree.json files and .tree.meta.json file
           --dumpi-<srcfile> <level>   Enable dumping everything in source file at level
           --dumpi-dfg <level>         Enable dumping DfgGraphs to .dot files at level
           --dumpi-graph <level>       Enable dumping V3Graphs to .dot files at level
           --dumpi-tree <level>        Enable dumping Ast .tree files at level
           --dumpi-tree-json <level>   Enable dumping Ast .tree.json files at level
            -E                         Preprocess, but do not compile
           --emit-accessors            Emit getter and setter methods for model top class
           --error-limit <value>       Abort after this number of errors
           --exe                       Link to create executable
           --expand-limit <value>      Set expand optimization limit
            -F <file>                  Parse arguments from a file, relatively
            -f <file>                  Parse arguments from a file
            -FI <file>                 Force include of a file
           --flatten                   Force inlining of all modules, tasks and functions
           --fourstate                 Enable fourstate logic
           --no-fourstate              Disable fourstate logic
           --func-recursion-depth <value>  Maximum recursive constant function depth
           --future0 <option>          Ignore an option for compatibility
           --future1 <option>          Ignore an option with argument for compatibility
            -fno-<optimization>        Disable internal optimization stage
            -G<name>=<value>           Overwrite top-level parameter
           --gate-stmts <value>        Tune gate optimizer depth
           --gdb                       Run Verilator under GDB interactively
           --gdbbt                     Run Verilator under GDB for backtrace
           --generate-key              Create random key for --protect-key
           --get-supported <feature>   Get if feature is supported
           --getenv <var>              Get environment variable with defaults
           --help                      Show this help
           --hierarchical              Enable hierarchical Verilation
           --hierarchical-block <block>  Internal use only for --hierarchical
           --hierarchical-child <block>  Internal use only for --hierarchical
           --hierarchical-params-file <name>  Internal option that specifies parameters file for hier blocks
           --hierarchical-threads <threads>  Number of threads for hierarchical scheduling
            -I<dir>                    Directory to search for includes
           --if-depth <value>          Tune IFDEPTH warning
            +incdir+<dir>              Directory to search for includes
           --inline-cfuncs <value>     Inline CFuncs with <=value nodes (0=off)
           --inline-cfuncs-product <value>  Inline CFuncs if size*calls <= value
           --inline-mult <value>       Tune module inlining
           --instr-count-dpi <value>   Assumed dynamic instruction count of DPI imports
            -j <jobs>                  Parallelism for --build-jobs/--verilate-jobs
           --no-json-edit-nums         Don't dump editNum in .tree.json files
           --no-json-ids               Don't use short identifiers instead of addresses/paths in .tree.json
           --json-only                 Create JSON parser output (.tree.json and .meta.json)
           --json-only-meta-output <filename>  Set .tree.meta.json output filename
           --json-only-output <filename>       Set .tree.json output filename
           --l2-name <value>           Verilog scope name of the top module
           --language <lang>           Default language standard to parse
            -LDFLAGS <flags>           Linker pre-object arguments for makefile
            -libmap                    Specify library mapping file
           --lib-create <name>         Create a DPI library
            +libext+<ext>+[ext]...     Extensions for finding modules
            +librescan                 Ignored for compatibility
           --lint-only                 Lint, but do not make output
           --localize-max-size <value>  Tune localize optimization variable size
           --main                      Generate C++ main() file
           --main-top-name             Specify top name passed to Verilated model in generated C++ main
           --make <build-tool>         Generate scripts for specified build tool
            -MAKEFLAGS <flags>         Arguments to pass to make during --build
           --max-num-width <value>     Maximum number width (default: 64K)
           --Mdir <directory>          Name of output object directory
           --MMD                       Create .d dependency files
           --mod-prefix <topname>      Name to prepend to lower classes
           --MP                        Create phony dependency targets
            +notimingchecks            Ignored
            -o <executable>            Name of final executable
            -O0                        Disable optimizations
            -O1                        Default optimizations
            -O2                        Stronger optimizations
            -O3                        High-performance optimizations
            -O<optimization-letter>    Selectable optimizations
           --output-groups <numfiles>  Group .cpp files into larger ones
           --output-split <statements>          Split .cpp files into pieces
           --output-split-cfuncs <statements>   Split model functions
           --output-split-ctrace <statements>   Split tracing functions
            -P                         Disable line numbers and blanks with -E
           --pins-bv <bits>            Specify types for top-level ports
           --pins-inout-enables        Specify that __en and __out signals be created for inouts
           --pins-sc-biguint           Specify types for top-level ports
           --pins-sc-uint              Specify types for top-level ports
           --pins-sc-uint-bool         Specify types for top-level ports
           --pins-uint8                Specify types for top-level ports
           --no-pins64                 Don't use uint64_t's for 33-64 bit sigs
           --pipe-filter <command>     Filter all input through a script
           --prefix <topname>          Name of top-level class
           --preproc-comments          Include preprocessor comments in the output with -E
           --preproc-defines           Include preprocessor defines in the output with -E
           --preproc-resolve           Include all found modules in the output with -E
           --preproc-token-limit       Maximum tokens on a line allowed by preprocessor
           --private                   Debugging; see docs
           --prof-c                    Compile C++ code with profiling
           --prof-cfuncs               Name functions for profiling
           --prof-exec                 Enable generating execution profile for gantt chart
           --prof-pgo                  Enable generating profiling data for PGO
           --protect-ids               Hash identifier names for obscurity
           --protect-key <key>         Key for symbol protection
           --protect-lib <name>        Create a DPI protected library
           --public                    Mark signals as public; see docs
           --public-depth <level>      Mark public to specified module depth
           --public-flat-rw            Mark all variables, etc as public_flat_rw
           --public-ignore             Ignore all public comment markings
           --public-params             Mark all parameters as public_flat
            -pvalue+<name>=<value>     Overwrite toplevel parameter
           --quiet                     Minimize additional printing
           --quiet-build               Don't print build progress
           --quiet-exit                Don't print the command on failure
           --quiet-stats               Don't print statistics
           --relative-includes         Resolve includes relative to current file
           --reloop-limit <value>      Minimum iterations for forming loops
           --replication-limit <value> Replication concatenation limit (default: 8k)
           --report-unoptflat          Extra diagnostics for UNOPTFLAT
           --rr                        Run Verilator and record with rr
           --runtime-debug             Enable model runtime debugging
           --savable                   Enable model save-restore
           --sc                        Create SystemC output
           --sched-zero-delay          Specify #0 delay support
           --no-skip-identical         Disable skipping identical output
           --stats                     Create statistics file
           --stats-vars                Provide statistics on variables
           --no-std                    Prevent loading standard files
           --no-std-package            Prevent parsing standard package
           --no-std-waiver             Prevent parsing standard lint waivers
           --no-stop-fail              Do not call $stop when assertion fails
            -sv                        Enable SystemVerilog parsing
            +systemverilogext+<ext>    Synonym for +1800-2023ext+<ext>
           --threads <threads>         Enable multithreading
           --threads-dpi <mode>        Enable multithreaded DPI
           --threads-max-mtasks <mtasks>  Tune maximum mtask partitioning
           --timescale <timescale>     Sets default timescale
           --timescale-override <timescale>  Overrides all timescales
           --timing                    Enable timing support
           --no-timing                 Disable timing support
           --top <topname>             Alias of --top-module
           --top-module <topname>      Name of top-level input module
           --trace                     Enable VCD waveform creation
           --trace-coverage            Enable tracing of coverage
           --trace-depth <levels>      Depth of tracing
           --trace-fst                 Enable FST waveform creation
           --trace-max-array <depth>   Maximum array depth for tracing
           --trace-max-width <width>   Maximum bit width for tracing
           --trace-params              Enable tracing of parameters
           --trace-saif                Enable SAIF file creation
           --trace-structs             Enable tracing structure names
           --no-trace-top              Do not emit traces for signals in the top module generated by verilator
           --trace-underscore          Enable tracing of _signals
           --trace-vcd                 Enable VCD waveform creation
            -U<var>                    Undefine preprocessor define
           --no-unlimited-stack        Don't disable stack size limit
           --unroll-count <loops>      Tune maximum loop iterations
           --unroll-limit <loops>      Maximum loop iterations before assuming infinite loop
           --unroll-stmts <stmts>      Tune maximum loop body size
           --unused-regexp <regexp>    Tune UNUSED lint signals
            -V                         Verbose version and config
            -v <filename>              Verilog library
           --valgrind                  Run Verilator under valgrind
           --no-verilate               Skip Verilation and just compile previously Verilated code
           --verilate-jobs             Job threads for Verilation stage
            +verilog1995ext+<ext>      Synonym for +1364-1995ext+<ext>
            +verilog2001ext+<ext>      Synonym for +1364-2001ext+<ext>
           --version                   Show program version and exits
           --vpi                       Enable VPI compiles
           --waiver-multiline          Create multiline --match for waivers
           --waiver-output <filename>  Create a waiver file based on linter warnings
            -Wall                      Enable all style warnings
            -Werror-<message>          Convert warnings to errors
            -Wfuture-<message>         Disable unknown message warnings
            -Wno-<message>             Disable warning
            -Wno-context               Disable source context on warnings
            -Wno-fatal                 Disable fatal exit on warnings
            -Wno-lint                  Disable all lint warnings
            -Wno-style                 Disable all style warnings
            -work <libname>            Set config library for following files
            -Wpedantic                 Warn on compliance-test issues
            -Wwarn-<message>           Enable specified warning message
            -Wwarn-lint                Enable lint warning message
            -Wwarn-style               Enable style warning message
           --x-assign <mode>           Assign non-initial Xs to this value
           --x-initial <mode>          Assign initial Xs to this value
           --x-initial-edge            Enable initial X->0 and X->1 edge triggers
            -y <dir>                   Directory to search for modules

       This is a short summary of the simulation runtime arguments, i.e. for
       the final Verilated simulation runtime models.  See
       <https://verilator.org/guide/latest/exe_verilator.html> for the
       detailed description of these arguments.

            +verilator+assert+lock                Lock assertion status changes at startup
            +verilator+coverage+file+<filename>   Set coverage output filename
            +verilator+debug                      Enable debugging
            +verilator+debugi+<value>             Enable debugging at a level
            +verilator+error+limit+<value>        Set error limit
            +verilator+help                       Show help
            +verilator+log+file+<filename>        Log stdout and stderr output to filename
            +verilator+noassert                   Disable assert checking
            +verilator+prof+exec+file+<filename>  Set execution profile filename
            +verilator+prof+exec+start+<value>    Set execution profile starting point
            +verilator+prof+exec+window+<value>   Set execution profile duration
            +verilator+prof+vlt+file+<filename>   Set PGO profile filename
            +verilator+quiet                      Minimize additional printing
            +verilator+rand+reset+<value>         Set random reset technique
            +verilator+seed+<value>               Set random seed
            +verilator+solver+file+<filename>     Set random solver log filename
            +verilator+V                          Show verbose version and config
            +verilator+version                    Show version and exit
            +verilator+vpi+<library>[:<bootstrap>]  Load VPI shared library
            +verilator+wno+unsatconstr+<value>    Disable constraint warnings

DISTRIBUTION
       The latest version is available from <https://verilator.org>.

       Copyright 2003-2026 by Wilson Snyder. This program is free software;
       you can redistribute it and/or modify the Verilator internals under the
       terms of either the GNU Lesser General Public License Version 3 or the
       Perl Artistic License Version 2.0.

       All Verilog and C++/SystemC code quoted within this documentation file
       are released as Creative Commons Public Domain (CC0).  Many example
       files and test files are likewise released under CC0 into effectively
       the Public Domain as described in the files themselves.

SEE ALSO
       verilator_coverage, verilator_gantt, verilator_profcfunc, make,

       "verilator --help" which is the source for this document,

       and <https://verilator.org/verilator_doc.html> for detailed
       documentation.

perl v5.42.2                      2026-09-05                      VERILATOR(1)