Combined the 3 various APIs used in EmitC* passes to handle file
opening/splitting into a single one. This removes a lot of copy paste
and makes everything consistent.
All C++ file handling goes through `EmitCBaseVisitor` using the
`openNewOutputHeaderFile`, `openNewOutputSourceFile` and
`closOutputFile` methods.
To emit a new kind of file, always derive a new class from
`EmitCBaseVisitor`, and use the above APIs, they will take care of
everything else in a consistent matter.
Subsequently also removed V3OutSCFile, and instead included
verilated_sc.h (which included the systemc header itself) in the two
files that need it (the primary model header, and the root module
header).
Functional changes:
- The PCH header did not use to have a corresponding AstCFile. Now it
does, though this makes no difference in the output
- All 'slow' sources now have '__Slow' in the name automatically (the
only one missing was for the ConstPool files)
Rest of the output is identical except for the header line now being
present in all generated C++ files.
Geza Lore
Wilson Snyder
Bartłomiej Chmiel