[ru551n]

Adds experimental support for yavs, a VHDL-2008 and VHDL-2019 simulator. You select it with VUNIT_SIMULATOR=yavs. It is registered last, so it is never picked automatically when another simulator is found.

What it does

• Libraries: each library is a directory that yavs creates on first analysis. --work/--map pass the project's libraries, and every file is analyzed with its own --std. 2008 and 2019 files can be mixed; other standards are rejected at setup.
• Simulation: yavs run, or yavs elab for --elaborate, with lib.entity.arch or a configuration as the top and -g generics. Everything after the subcommand goes through a response file, which keeps long generics such as runner_cfg clear of command-line length and quoting limits. --exit-severity follows vhdl_assert_stop_level, and the simulator hooks' elab/run flags and environment are applied.
• --gui: runs yavs run --gui with the arguments of the normal run, which opens it in yavs-gui.
• Options and marker: yavs.global_flags, yavs.a_flags, yavs.elab_flags, yavs.sim_flags, and a yavs_version package marker.
• Version check: yavs --version is checked at setup.

Needs a change in vunit-osvvm

As for JanusHDL (#1248), vunit_pkg.toml in vunit-osvvm picks a CoverageVendorApiPkg variant by simulator name, so yavs gets none, and random and verification_components fail to analyze. Adding simulator == "yavs" to the CoverageVendorApiPkg_default.vhd condition fixes it. I verified that locally.

Testing (yavs 0.8.0 release, Linux x86-64)

• All vunit/vhdl/*/run.py suites except python pass: 1338 of 1338 (check, com, data_types, dictionary, logging, path, random, run, string_ops, verification_components). The random and verification_components results include the vunit-osvvm change above.
• tests/acceptance/test_artificial.py, test_dependencies.py and the new test_yavs_fake.py (against a fake yavs script) pass, with one exception: lib.tb_ieee_warning.pass fails, because yavs 0.8.0 ignores --ieee-warnings=off (yavs#836). The interface passes the flag correctly.
• New tests/unit/test_yavs_interface.py. The rest of tests/unit passes. pylint, pycodestyle, black and the license test are clean on the new files.

Left out for follow-ups

• --batch-compile and --parallel-compile: yavs supports both, since it locks its libraries, but they depend on Add --batch-compile to compile files of a library in one call #1236 and Add -j to compile files in parallel #1235.
• A --debug flag: it would run one test under the yavs debug adapter, but it needs a new hook for checking the test selection.

🤖 Generated with Claude Code

[ru551n]

Closing: simulators are now added through packages instead of being built into VUnit, see #1250. (Comment written by Claude on behalf of ru551n.)