How is these library thing working?

[tmeissner]

I'm trying to compile some files into a library called libvhdl and afterwards other files which use this library. But nvc can't find the compiled library. I'm not sure that I understand the --work and -L option correctly.

In my understanding, --work x:y compiles files into library with name x into a directory named y. If I want to use the library later, I have to use -L with parameter y. Correct?

What I do is this, but it's not working:

/usr/local/bin/nvc --std=08 -L work/ --work=libvhdl:work -a ../ext/libvhdl/common/UtilsP.vhd  &&  \
/usr/local/bin/nvc --std=08 -L work/ --work=work:work -a ../ext/libvhdl/syn/*.vhd ../ext/cryptocores/aes/rtl/vhdl/*.vhd 
** Note: pass --psl to enable parsing of PSL directives in comments
     > ../ext/libvhdl/syn/SpiMasterE.vhd:234
     |
 234 |   -- psl default clock is rising_edge(Clk_i);
     |   ^^^^^^^
** Error: library LIBVHDL not found
    > ../ext/libvhdl/syn/UartRx.vhd:25
    |
 25 | library libvhdl;
    | ^^^^^^^^^^^^^^^^
    |
    = Note: library search path contains: work/, /root/.nvc/lib, /usr/local/lib/nvc
    = Note: add additional directories to the search path with the -L option
** Fatal: required library LIBVHDL not found
** Note: library search path contains: work/, /root/.nvc/lib, /usr/local/lib/nvc
** Note: add additional directories to the search path with the -L option

There are some files unter work/, so why isn't nvc find the libraries?

$ ls work/
LIBVHDL.UTILSP  LIBVHDL.UTILSP-body  _NVC_LIB  _index

[Anselmo95]

Hello, I think you just need to do "-L ./"
By passing "work/" I think NVC is looking inside this folder but the library is the folder itself so you need to pass the parent directory

[tmeissner]

Thanks for your hint. Unfortunately it doesn't work, the result is exactly the same.

The other thing is, does every library has to be in its own separate folder? Or are the distinguished by their file names?

[Anselmo95]

I was looking at the help message and I don't see the x:y format for the --work option as you said in your message.
I would try to do this:

/usr/local/bin/nvc --std=08 -L./ --work=libvhdl -a ../ext/libvhdl/common/UtilsP.vhd  &&  \
/usr/local/bin/nvc --std=08 -L./ --work=work -a ../ext/libvhdl/syn/*.vhd ../ext/cryptocores/aes/rtl/vhdl/*.vhd 

I have used libraries a little before, from what I remember NVC crates the folder for each library so you just need to use -L./ to include the current directory where the libraries are created and pass the name of your library to --work.

[nickg]

The -L argument sets the search path so when NVC encounters library foo, and it doesn't already know about a library named "foo", it will search each entry in the search path for a directory named foo and then checks whether that directory contains a valid NVC library.

But here the library libvhdl is actually inside a directory called work so it won't be found just by looking through the search path. In that case you need to tell NVC explicitly where the library is using the --map argument e.g. --map libvhdl:work.

One issue here is that both libraries libvhdl and work end up in the same physical directory called work. I hadn't considered this case and I'm not sure whether it works correctly or not. I should either write a test for it or detect it and issue an error. The intent is that each library lives in a separate directory.

Here's an example:

# All design units from utils.vhd get placed in library libvhdl in directory dir1
nvc --work=libvhdl:dir1 -a utils.vhd

# All design units from test.vhd get placed in library tb in directory dir2
# Any references to library libvhdl will be looked up in dir1
nvc --work=tb:dir2 --map libvhdl:dir1 -a test.vhd

# Elaborate and run design unit top from library tb
nvc --work=tb:dir2 --map libvhdl:dir1 -e top -r

Does that make sense? Unless you have special requirements its easiest to just keep one directory per library with the library name the same as the directory name and not use the x:y syntax.

[tmeissner]

Thanks for your explanation.

I want to compile all library folders in a sub directory called (for testing purposes) foobar, so I ended in this working solution:

mkdir -p foobar
/usr/local/bin/nvc --std=08 --work=libvhdl:foobar/libvhdl -a ../ext/libvhdl/common/UtilsP.vhd  &&  \
/usr/local/bin/nvc --std=08 --work=work:foobar/work -L foobar -a ../ext/libvhdl/syn/*.vhd ../ext/cryptocores/aes/rtl/vhdl/*.vhd

Compile seems to work now. But before I get further I have to clean my VHDL files from inline PSL constructs which I use with GHDL 😉

[nickg]

As a short-cut you can also use --work=foobar/libvhdl which is the same as --work=libvhdl:foobar/libvhdl.