Building and running most basic Verilator

Question

Trying to get started with basic Verilator c++ example on Windows 10.

Attempt 1: Using WSL, install from apt

• apt install verilator seems to run fine

• verilator --version returns Verilator 4.038 2020-07-11 rev v4.036-114-g0cd4a57ad

• export VERILATOR_ROOT=/usr/share/verilator (after a few attempts at this step)

• Using our.v and sim_main.cpp as in the example

• verilator --cc --exe --build -j 0 -Wall sim_main.cpp our.v returns %Error: -j accepts positive integer, but 0 is passed. Ok so maybe that's a version 5 argument.

• Try again verilator --cc --exe --build -j 1 -Wall sim_main.cpp our.v returns

    Can't exec "/usr/share/verilator/verilator_bin": No such file or directory at /usr/bin/verilator line 173.
    %Error: verilator: Misinstalled, or VERILATOR_ROOT might need to be in environment
    %Error: Verilator threw signal -1. Suggest trying --debug --gdbbt
    %Error: Command Failed /usr/share/verilator/verilator_bin --cc --exe --build -j 1 -Wall sim_main.cpp our.v
  

• verilator_bin is installed next to verilator in /usr/bin, not in /usr/share/verilator which is where VERILATOR_ROOT points to.

• When I had VERILATOR_ROOT accidentally pointing to /usr/bin in third step above, the tool could not find verilated.mk

• I went into obj_dir/ and did make Vour directly, but it complained about not finding verilated_heavy.h

• So it looks like VERILATOR_ROOT is the main lever here, and pointing to either /usr/bin or /usr/share/verilator doesn't work, but in different ways.

Attempt 2: Using WSL, build V5.008 from git source, from instructions

• apt remove verilator to remove attempt 1

• Download from git and build everything as per "Git Quick Install" section

• Needed to install help2man before make install, which is not in instructions

• verilator --version returns Verilator 5.008 2023-03-04 rev v5.008-32-gaaaf8e75a

• make test -- all passed

• which verilator returns /usr/local/bin/verilator

• export VERILATOR_ROOT=/usr/local/bin then verilator --cc --exe --build -j 0 -Wall sim_main.cpp our.v returns Cannot find verilated_std.sv``/usr/local/share/verilator/include/verilated_std.sv.

• Put export VERILATOR_ROOT=/usr/local/share/verilator in .bashrc, then restart, then verilator --cc --exe --build -j 0 -Wall sim_main.cpp our.v returns

    Can't exec "/usr/local/share/verilator/verilator_bin": No such file or directory at /usr/local/bin/verilator line 207.
    %Error: verilator: Misinstalled, or VERILATOR_ROOT might need to be in environment
    %Error: Verilator threw signal -1. Suggest trying --debug --gdbbt
    %Error: Command Failed /usr/local/share/verilator/verilator_bin --cc --exe --build -j 1 -Wall sim_main.cpp our.v
  

• So basically same problem as attempt #1 -- I can't find a good setting for VERILATOR_ROOT

• Checked https://github.com/verilator/verilator/issues/1116

• Removed VERILATOR_ROOT from .bashrc, start WSL again

• make clean, autoconf, make, make test, make install all good

• Same results as above after updating VERILATOR_ROOT to /usr/local/share/verilator and optionally adding $VERILATOR_ROOT/bin to path.

Attempt 3: Using MSVC and CMAKE, build V5.008 from git source

• More difficulties, but eventually got a binary
• Program does not generate any output.

Answer 1

I just needed to unset VERILATOR_ROOT completely, even after make install.