For example the pattern:
```
%e = load %1 : SomeEnum
switch_enum %e
```
The switch_enum_addr should reuse the load's address operand instead of
creating a new location for the SSA value of %e.
While we are there also don't create a new stack location for extracting payload
in a switch_enum_addr case target basic block if that extracted payload is not
used. That is if the basic block arguments in all switch target blocks are
unused in the switch_enum version.
```
switch_enum %enum, case #Optional.some!enumelt: bb1,
case #Optional.none!enumelt: bb2
bb2(%payload : $Payload):
// unused %payload value
```
rdar://156602951
We insert end_cow_mutation_addr for lifetime dependent values dependent on mutable addresses.
end_cow_mutation_addr can be simplified to end_cow_mutation after other optimizations like inlining, specialization etc
This PR adds an instruction simplification to transform end_cow_mutation_addr to end_cow_mutation.
This can enable array optimizations which look for end_cow_mutation.
This is a value operation that can work just fine on lowered types,
so there's no need to carry along a formal type. Make the value/address
duality clearer, and enforce it in the verifier.
Create two versions of the following functions:
isConsumedParameter
isGuaranteedParameter
SILParameterInfo::isConsumed
SILParameterInfo::isGuaranteed
SILArgumentConvention::isOwnedConvention
SILArgumentConvention::isGuaranteedConvention
These changes will be needed when we add a new convention for
non-trivial C++ types as the functions will return different answers
depending on whether they are called for the caller or the callee. This
commit doesn't change any functionality.
Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
It needs to match with the (large loadable) lowered closure type in the rest of
the program: Large types in the signature need to be passed indirectly.
rdar://127367321
An unchecked_trivial_bit_cast can go from a bigger type to a smaller
type. Therefore we must allocate stack storage for the operand type
rather than the result type. Otherwise, we can end up storing bigger
values into smaller storage -- not good.
rdar://128086028
LoadableByAddress was losing debug info, including at -Onone.
When converting a load-store pair to a copy_addr, the debug info
attached to the load was not salvaged.
Additionally, the wrong scope was being attached to other debug
values.
They can lower to a set of i64 registers we consider small but exploded
to (manifested as SSA) registers they will cause significant code bloat.
rdar://125265576
For years, optimizer engineers have been hitting a common bug caused by passes
assuming all SILValues have a parent function only to be surprised by SILUndef.
Generally we see SILUndef not that often so we see this come up later in
testing. This patch eliminates that problem by making SILUndef uniqued at the
function level instead of the module level. This ensures that it makes sense for
SILUndef to have a parent function, eliminating this possibility since we can
define an API to get its parent function.
rdar://123484595
Functions with c convention can have large direct arguments that are not
re-written by the LoadableByAddress pass before they get to reg2Mem
optimization.
https://github.com/apple/swift/issues/71757
In preparation for inserting mark_dependence instructions for lifetime
dependencies early, immediately after SILGen. That will simplify the
implementation of borrowed arguments.
Marking them unresolved is needed to make OSSA verification
conservative until lifetime dependence diagnostics runs.
Pattern:
%f = function_ref @invocationClosure : $@convention(thin) (BigStruct) -> ()
%s = struct $InvocationWrapper (%f : $@convention(thin) (BigStruct) -> ())
Error:
Unhandled use of FunctionRefInst
UNREACHABLE executed at /swift/lib/IRGen/LoadableByAddress.cpp:3057!
This fix simply adds the unrecognized case. Rewriting a function_ref
does not change its value, so I'm not sure why the assert exists in
the first place.
Optionally, the dependency to the initialization of the global can be specified with a dependency token `depends_on <token>`.
This is usually a `builtin "once"` which calls the initializer for the global variable.
The dependent 'value' may be marked 'nonescaping', which guarantees that the
lifetime dependence is statically enforceable. In this case, the compiler
must be able to follow all values forwarded from the dependent 'value', and
recognize all final (non-forwarded, non-escaping) use points. This implies
that `findPointerEscape` is false. A diagnostic pass checks that the
incoming SIL to verify that these use points are all initially within the
'base' lifetime. Regular 'mark_dependence' semantics ensure that
optimizations cannot violate the lifetime dependence after diagnostics.
I am doing this in preparation for adding options to SILParameterInfo/
SILResultInfo that state that a parameter/result is transferring. Even though I
could have just introduced a new bit here, I instead streamlined the interface
of SILParameterInfo/SILResultInfo to use an OptionSet instead of individual bits
to make it easier to add new flags here. The reason why it is easier is that
along API (e.x.: function argument) boundaries one does not have to marshal each
field or pass each field. Instead one can just pass the whole OptionSet as an
opaque thing. Using this I was able to change serialization/deserialization of
SILParameterInfo/SILResultInfo so that one does not need to update them if one
adds new fields!
The reason why I am doing this for both SILParameterInfo/SILResultInfo in the
same commit is because they share code in the demangler that I did not want to
have to duplicate in an intervening commit. By changing them both at the same
type, I didn't have to change anything without an actual need to.
I am doing this in a separate commit from adding transferring support so I can
validate correctness using the tests for the options already supported
(currently only differentiability).
LoadableByAddress was accidentally changing ownership of
direct_unowned values to @in (owned). This generates unsupported SIL
for on-stack partial applies, which now breaks SIL verification.
This also resulted in extra copies of values inside of closure
contexts. Before calling the original function, the value would need to
be copied onto the stack and the context would be destroyed. Now, we
simply pass a pointer directly from the closure context. See
IRGen/indirect_argument.sil+huge_partial_application.
I'm pretty sure fixing this has no effect on the mangling of public symbols.
The `bare` attribute indicates that the object header is not used throughout the lifetime of the value.
This means, no reference counting operations are performed on the object and its metadata is not used.
The header of bare objects doesn't need to be initialized.
