Continue cleaning up shadowed variables, flagged by turning on -Wshadow.
No intended change in functionality. This patch set covers the tgt-vhdl
directory, and was tested by Nick.
Emitting a VHDL expression like Resize("01", 32) is ambiguous
between interpreting "01" as a Signed or an Unsigned. There's
no point actually outputting this as we can sign-extend the
constant value in the code generator, which is what this
patch does.
This splits up the monolithic and confusing vhdl_expr::cast function into
several smaller to_XXX functions which each generate code to cast an
expression to type XXX. This makes it much easier to understand and maintain.
Mostly this ensures that a recursive call to a function
is made with the correct types (this may involve generating
code to cast expressions to the correct type).
Combinatorial UDPs will be implemented with a `with ... select'
statemetnt. However the input to this must be "locally static".
This patch joins the inputs into a vector which can be used as
the select expression.