iverilog `-tvvp` generates non-relocatable absolute VPI module paths

[rhabacker]

Description

The vvp target generated by iverilog -tvvp embeds absolute paths for built-in VPI modules into the generated .vvp file.

The VVP target format documentation explicitly shows generated :vpi_module entries:
[VVP target documentation]

Example from the documentation:

:vpi_module "/usr/local/lib/ivl/system.vpi";

Observed example on Windows/MSYS2:

:vpi_module "Z:\usr\X86_~FWL\sys-root\mingw\lib\ivl\system.vpi";

This causes generated .vvp files to become non-portable and non-relocatable.

Problem

The generated paths depend on:

• the configure-time --prefix
• the build machine layout
• MinGW/MSYS path translation
• short-path expansion on Windows
• the installation root used during packaging

This becomes especially problematic when using staged installs via DESTDIR.

Example:

./configure --prefix=/usr
make
make DESTDIR=/tmp/pkg install

The generated .vvp files still contain paths derived from the configured prefix or build environment, even if the final installation location differs.

As a result:

• .vvp files are not relocatable
• packaged artifacts may fail on target systems
• CI-generated outputs are machine-dependent
• reproducible builds are harder
• Windows builds leak temporary or synthetic paths

Expected Behavior

The generated .vvp file should not embed absolute install paths for built-in VPI modules.

[caryr]

I agree the normal internal libraries should be relocatable. We need to think about what is needed for custom libraries. Should they also be relocatable and we then need to pass in their location or should they us a full path? I tend to think they should also be relocatable.

[rhabacker]

I agree the normal internal libraries should be relocatable.

This will be fixed with #1354

We need to think about what is needed for custom libraries. Should they also be relocatable and we then need to pass in their location or should they us a full path? I tend to think they should also be relocatable.

I have added an additional test to the examples directory as a starting point that uses the new command-line options, and the generated VVP file contains relocatable VPI module entries. If other or additional configurations are needed to verify this support, please provide guidance on how to add the appropriate test cases.