Change WDataInP/WDataOutP to be opaque handles types instead of aliases
to raw pointers. This subsequently eliminates needing an implicit cast
operator in VlWide, which is replaced with implicit constructors of
WDataInP/WDataOutP that can create a handle from a VlWide. This
eliminates some unsafe conversions that the previous implicit cast
operator unintentionally enabled (e.g. #7618). It also eliminates
having to insert ".data()" in various places int he generated code, which
simplifies internals (the only place ".data()" should be needed is in
calls to variadic functions where the expected type of the argument is
not WDataInP/WDataOutP).
The handles otherwise behave like pointers, implementing the minimal
amount of operators required to code the runtime. The handle is still
only a single pointer, and will be passed in registers as before, so
this patch should be performance neutral.
As part of this removed WData, which used to be an alias for EData.
All uses are now either EData*, WDataInP, WDataOutP, or VlWide directly.
This patch introduces the concept of 'loose' methods, which semantically
are methods, but are declared as global functions, and are passed an
explicit 'self' pointer. This enables these methods to be declared
outside the class, only when they are needed, therefore removing the
header dependency. The bulk of the emitted model implementation now uses
loose methods.