`VlNow{}` is completely unnecessary, as coroutines are always on the
heap (unless optimized out). Also fix access of var ref passed to forked processes.
Given an await at the end of a block, e.g. at the end of a loop body, a trace
activity setter was not inserted, as there were no following statements. This
patch makes the activity update unconditional.
Before this patch, it was possible to access non-static class members using
static access, which resulted in C++ compilation errors. This adds
verilation-time checks for such situations.
1. Fixes passing a null reference as a task argument. Before this patch it would
cause a C++ compile error like `cannot convert ‘VlNull’ to ‘VlClassRef<...>’`.
2. Fixes passing a class reference as a task argument when the argument is a
reference to a base class. Before the patch it would cause a C++ compile
error like `cannot convert ‘VlClassRef<{DERIVED_CLASS}>’ to ‘VlClassRef<{BASE_CLASS}>`.
Before this patch, calling tasks directly under forks would result in each
statement of these tasks being executed concurrently. This was due to Verilator
inlining tasks most of the time. Such inlined tasks' statements would simply
replace the original call, and there would be no indication that these used to
be grouped together. Ultimately resulting in `V3Timing` treating each statement
as a separate process.
The solution is simply to wrap each fork sub-statement in a begin in `V3Begin`
(except for the ones that are begins, as that would be pointless). `V3Begin` is
already aware of forks, and is supposed to avoid issues like this one, so it
seems like a natural fit. This also protects us from similar bugs, i.e. if some
statement gets replaced or expanded into multiple statements.
Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>
