rdar://132501359
PowerOf2Ceil is not the correct function to use, because we end up with an empty mask if there is only one value stored in the extra tag bits
rdar://129627898
When casting the projectedBits to Int8, we accidetnally passed the base addr instead of the projectedBits. This was causing the wrong bits to be read.
We have had a heuristic that lets you reflect fields of types, where
the field's type is conditionally Copyable, despite the reflection
infrastructure always copying a field. That heuristic was added to allow
ubiquitous types like Optional in the stdlib to continue to be
reflected, even if the Optional at runtime really isn't Copyable.
As a consequence, we were also allowing reflection of fields containing
user-defined conditionally copyable types, when that's unsafe for no
real benefit, yielding runtime crashes!
I think in that case it's better to fall-back on the non-crashy case of
reflection seeing it as the EmptyTupleType, which isn't inhabited, so it
won't try to copy the field and instead basically skip-over it until a
future runtime supports the reflection safely.
So, this patch limits the dangerous reflection to only stdlib-defined
types, until Mirror and friends are updated.
We generally should use the open-coded, metadata function "accessor"
strategy when targeting older runtimes, but if the type is part of
the stdlib, assume the runtime demangler will produce correct
metadata, as the retrofitting of Optional, etc, was done Carefully.
resolves rdar://131337585
rdar://129359370
Second part of direct error support. This implements direct errors for async functions. Instead of always returning typed errors indirectly, we are returning them directly when possible.
Instead of adding opaque fields for the base subobjects this patch
introduces a recursive walk to add all the base fields to the generated
Swift struct.
rdar://126754931
In most cases this was already checked with `ClassLayout::isFixedLayout`. But for classes which are imported from another module and contain implementation-only C-imported stored properties, those properties don't show up in the class layout. Stack promoting such classes will reserve too less space on the stack which leads to all kind of memory corruption problems. The fix is to also check `ClassLayout::isFixedSize`, which returns false for such classes.
Fixes a miscompile
rdar://131067105
rdar://129627898
LLVM expects integer types of fractional byte sizes to have been written as those types as well, so it expects all unused bytes to be 0.
Since we are using the unused extra tag bits to store tags of outer enums, that assumption does not hold here. In regular witnesses,
the outer enum would mask out those bytes before checking the tag of the inner enum. In CVW we can't do that, so we have to apply the
mask ourselves. To guarantee the mask does not get optimized out, we have to use full bytes instead of fractionals.
