This is a subset of #68288, with hopefully narrower scope. It does not
support bitcasting to non-integral types yet.
Bitfields are supported, but only if they result in a full byte-sized
final buffer. It does not support casting from null-pointers yet or
casting from indeterminate bits.
The tests are from #68288 and partially from #74775.
The `BitcastBuffer` struct is currently always working in single bits,
but I plan to (try to) optimize this for the common full-byte case.
Implement constexpr vector unary operators +, -, ~ and ! .
- Follow the current constant interpreter. All of our boolean operations
on vector types should be '-1' for the 'truth' type.
- Move the following functions from `Sema` to `ASTContext`, because we
used it in new interpreter.
```C++
QualType GetSignedVectorType(QualType V);
QualType GetSignedSizelessVectorType(QualType V);
```
---------
Signed-off-by: yronglin <yronglin777@gmail.com>
I started out by adding a new pointer type for blocks, and I was fully
prepared to compile their AST to bytecode and later call them.
... then I found out that the current interpreter doesn't support
calling blocks at all. So we reuse `Function` to support sources other
than `FunctionDecl`s and classify `BlockPointerType` as `PT_FnPtr`.
