It's not forming the metatype for the protocol type (exists t: P. t).metatype, it's forming the existential of a metatype of a conforming type, exists t: P. (t.metatype).
Swift SVN r14520
Having one instruction to get the dynamic metatype of a (non-existential) value makes more sense from a generic specialization standpoint and should stave off inevitable crashers when archetype_metatypes get specialized. protocol_metatype remains separate because metatype existentials are more interesting.
Swift SVN r14499
We were wantonly applying 'upcast' to archetypes in some cases, and really, that's OK, since these instructions do the same thing (and generic specialization could turn archetype_ref_to_super into upcast). Make everyone's life easier by folding archetype_to_super into upcast. Fixes <rdar://problem/16192324>.
Swift SVN r14496
Introduce the SIL instructions thick_to_objc_metatype and
objc_to_thick_metatype to convert between the 'thick' and
'Objective-C' representations of a metatype. Most of this code is
trivial support code for these conversions: printing, parsing,
(de-)serialization, etc., for which testing will come online in
subsequent patches or is incidental in other tests.
Lower Objective-C metatype values down to objc_class* at the IR level
and implement IRGen support for these SIL instructions. SIL-only test
case at the moment because SILGen never creates these instructions.
Swift SVN r14087
A SILArgument is a function argument if the argument's parent BB is the entry BB
of the function containing the argument.
This is an interesting distinction since function arguments have special
aliasing properties with respect to indirect arguments which normal basic block
arguments do not.
Swift SVN r14012
Riding off of project_existential[_ref] was convenient, but the
resuls are used quite differently. Note that open_existential[_ref]
still don't print/parse reasonably yet.
Swift SVN r13878
future variadic address projections land, getUnderlyinObject and
findAddressProjectionPath should never disagree due to the former handling casts
in contrast with the later.
Swift SVN r13769
