There's a group of methods in `DeclContext` with names that start with *is*,
such as `isClassOrClassExtensionContext()`. These names suggests a boolean
return value, while the methods actually return a type declaration. This
patch replaces the *is* prefix with *getAs* to better reflect their interface.
This allows devirtualization of witness method calls if the initialization of the existential is not in the same basic block.
This change also fixes a bug where promotion is done even if the stack is overwritten after initialization. Although I'm not sure if this kind of code is ever generated.
As there are no instructions left which produce multiple result values, this is a NFC regarding the generated SIL and generated code.
Although this commit is large, most changes are straightforward adoptions to the changes in the ValueBase and SILValue classes.
While I'm in this code, generalize it to propagate the original
type information in more cases, including when the original type
is still dependent, and teach it to handle existential metatypes.
rdar://24114020
This eliminates some minor overheads, but mostly it eliminates
a lot of conceptual complexity due to the overhead basically
appearing outside of its context.
The main idea here is that we really, really want to be
able to recover the protocol requirement of a conformance
reference even if it's abstract due to the conforming type
being abstract (e.g. an archetype). I've made the conversion
from ProtocolConformance* explicit to discourage casual
contamination of the Ref with a null value.
As part of this change, always make conformance arrays in
Substitutions fully parallel to the requirements, as opposed
to occasionally being empty when the conformances are abstract.
As another part of this, I've tried to proactively fix
prospective bugs with partially-concrete conformances, which I
believe can happen with concretely-bound archetypes.
In addition to just giving us stronger invariants, this is
progress towards the removal of the archetype from Substitution.
Having a separate address and container value returned from alloc_stack is not really needed in SIL.
Even if they differ we have both addresses available during IRGen, because a dealloc_stack is always dominated by the corresponding alloc_stack in the same function.
Although this commit quite large, most changes are trivial. The largest non-trivial change is in IRGenSIL.
This commit is a NFC regarding the generated code. Even the generated SIL is the same (except removed #0, #1 and @local_storage).
This is something that we have wanted for a long time and will enable us to
remove some hacks from the compiler (i.e. how we determine in the ARC optimizer
that we have "fatalError" like function) and also express new things like
"noarc".
Debug variable info may be attached to debug_value, debug_value_addr,
alloc_box, and alloc_stack instructions.
In order to write textual SIL -> SIL testcases that exercise the handling
of debug information by SIL passes, we need to make a couple of additions
to the textual SIL language. In memory, the debug information attached to
SIL instructions references information from the AST. If we want to create
debug info from parsing a textual .sil file, these bits need to be made
explicit.
Performance Notes: This is memory neutral for compilations from Swift
source code, because the variable name is still stored in the AST. For
compilations from textual source the variable name is stored in tail-
allocated memory following the SIL instruction that introduces the
variable.
<rdar://problem/22707128>
(libraries now)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
