This patch adds some abstract enums to pass to the trace decl* APIs, so
the VCD/FST specific code can be kept in verilated_{vcd,fst}_*.cc, and
removed from V3Emit*. It also reworks the generation of the trace init
functions (those that call 'decl*' for the signals) such that the scope
hierarchy is traversed precisely once during initialization, which
simplifies the FST writer. This later change also has the side effect of
fixing tracing of nested interfaces when traced via an interface
reference - see the change in the expected t_interface_ref_trace - which
previously were missed.
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.
Wilson Snyder
Geza Lore
Krzysztof Bieganski
Yves Mathieu