verilator
Support disabling blocks containing forks
It adds support for disabling blocks that contain forks, but aren't inside forks themselves.
The handling is similar to the ones of previous cases. For each disable statement a queue of std::process is created which contains processes that entered into the block to which the disable statement points to. The disable statement is replaced with the call of disableFork on each element of the queue and a jump to the end of the block.
Currently, the test I temporarily committed gives wrong results: https://github.com/antmicro/verilator/commit/80ba0e38f176f55fab92ee51a3613a7776758736. It is because it enters into this case: https://github.com/antmicro/verilator/blob/7a61f8a55fb5d429273a8119f498512c1acd1fa7/src/V3LinkJump.cpp#L426-L430 (even on master). I wanted to merge this case with the case above (which I added in this PR), but it broke a few tests. Some of them started requiring the --timing flag and at least one failed because the usage of std::process was added to the function that is used on the RHS of the parameter assignment and as a result, that function stopped being constant. This test is https://github.com/verilator/verilator/blob/7d4e5595d06fe971449eb17faeef4f8628549fe1/test_regress/t/t_unroll_nested_param.v.
Another thing that I committed and reverted is throwing UNSUPPORTED warning on disable statement pointing to a block that is inside a function. In such a case we can't detect if that function is called inside a fork and if it is, it will be handled wrong. It broke existing tests, such as t_altera_lpm_ram_dp, because its code contains disable pointing to a block that is inside a task: https://github.com/verilator/verilator/blob/7d4e5595d06fe971449eb17faeef4f8628549fe1/test_regress/t/t_altera_lpm.v#L280
These two problems exist currently on master, I just found them during the work on this PR. Do you have any idea what to do with them? The best thing that comes to my mind is to restore my reverted commits, but use the old handling in case when no forks are present in the user code.
and at least one failed because the usage of std::process was added to the function that is used on the RHS of the parameter assignment and as a result, that function stopped being constant. This test is https://github.com/verilator/verilator/blob/7d4e5595d06fe971449eb17faeef4f8628549fe1/test_regress/t/t_unroll_nested_param.v.
The disables in that are all to exit the loop, they should be becoming JumpGo's and shouldn't ever get std::process added. Maybe you are adding std::process too soon? Likewise the altera READER.
This happened when I merged handling of two cases into one: https://github.com/verilator/verilator/pull/6514/commits/029bf3e29bf080ebd8099d5dc4a20fc835c55634, which was required to make the test https://github.com/antmicro/verilator/commit/80ba0e38f176f55fab92ee51a3613a7776758736 pass.
If you think this is ready please merge in master, fix conflicts, and let me know and will give it another review pass, thanks.
What is left to do is what you proposed in the comment. I stopped working on this PR, because I need to focus on other things. I will come back to it later.