The issue here is that the demangler (since we have a postfix mangling) parses
parameters/results/etc and then uses earlier postfix type arguments to attach
the relevant types to the parameters/results/etc. Since the flag for a sending
result was placed in between the parameters and results, we get an off by one
error.
Rather than fix that specific issue by introducing an offset for the off by one
error, I used the fact that the impl-function part of the mangling is not ABI
and can be modified to move the bit used to signify a sending result to before
the parameters so the whole problem is avoided.
I also while I was doing this looked through the sending result mangling for any
further issues and fixed them as I found them.
rdar://141962865
`Builtin.FixedArray<let N: Int, T: ~Copyable & ~Escapable>` has the layout of `N` elements of type `T` laid out
sequentially in memory (with the tail padding of every element occupied by the array). This provides a primitive
on which the standard library `Vector` type can be built.
Mangling this information for future directions like component lifetimes
becomes complex and the current mangling scheme isn't scalable anyway.
Deleting this support for now.
Some requirement machine work
Rename requirement to Value
Rename more things to Value
Fix integer checking for requirement
some docs and parser changes
Minor fixes
Instead of adding a "flag" (`m` in `...Tgm5`) make it more generic to allow to drop any unused argument.
Add all dropped arguments with a `t<n-1>` (where `<n-1>` is empty for n === 0). For example `...Ttt2g5`.
They are not used. Demangling uses `assert()` from <cassert>,
and macros from lib/Demangling/DemanglerAssert.h.
Reverts the lib/Demangling changes from #74184.
No behavior change.
This corresponds to the parameter-passing convention of the Itanium C++
ABI, in which the argument is passed indirectly and possibly modified,
but not destroyed, by the callee.
@in_cxx is handled the same way as @in in callers and @in_guaranteed in
callees. OwnershipModelEliminator emits the call to destroy_addr that is
needed to destroy the argument in the caller.
rdar://122707697
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)
We still only parse transferring... but this sets us up for adding the new
'sending' syntax by first validating that this internal change does not mess up
the current transferring impl since we want both to keep working for now.
rdar://128216574
Replace use of `snprintf()` with some custom code (this is around 10x
faster on my machine).
Move a few of the `Node` member functions to the header so they're
inlined.
Optimize the `deepEquals()` function by adding an `isSimilarTo()`
method on `Node`; the checks that were happening in the `deepEquals()`
function could be implemented more efficiently by making use of
details of the internal representation of `Node`.
rdar://125739630
This PR implements first set of changes required to support autodiff for coroutines. It mostly targeted to `_modify` accessors in standard library (and beyond), but overall implementation is quite generic.
There are some specifics of implementation and known limitations:
- Only `@yield_once` coroutines are naturally supported
- VJP is a coroutine itself: it yields the results *and* returns a pullback closure as a normal return. This allows us to capture values produced in resume part of a coroutine (this is required for defers and other cleanups / commits)
- Pullback is a coroutine, we assume that coroutine cannot abort and therefore we execute the original coroutine in reverse from return via yield and then back to the entry
- It seems there is no semantically sane way to support `_read` coroutines (as we will need to "accept" adjoints via yields), therefore only coroutines with inout yields are supported (`_modify` accessors). Pullbacks of such coroutines take adjoint buffer as input argument, yield this buffer (to accumulate adjoint values in the caller) and finally return the adjoints indirectly.
- Coroutines (as opposed to normal functions) are not first-class values: there is no AST type for them, one cannot e.g. store them into tuples, etc. So, everywhere where AST type is required, we have to hack around.
- As there is no AST type for coroutines, there is no way one could register custom derivative for coroutines. So far only compiler-produced derivatives are supported
- There are lots of common things wrt normal function apply's, but still there are subtle but important differences. I tried to organize the code to enable code reuse, still it was not always possible, so some code duplication could be seen
- The order of how pullback closures are produced in VJP is a bit different: for normal apply's VJP produces both value and pullback closure via a single nested VJP apply. This is not so anymore with coroutine VJP's: yielded values are produced at `begin_apply` site and pullback closure is available only from `end_apply`, so we need to track the order in which pullbacks are produced (and arrange consumption of the values accordingly – effectively delay them)
- On the way some complementary changes were required in e.g. mangler / demangler
This patch covers the generation of derivatives up to SIL level, however, it is not enough as codegen of `partial_apply` of a coroutine is completely broken. The fix for this will be submitted separately as it is not directly autodiff-related.
---------
Co-authored-by: Andrew Savonichev <andrew.savonichev@gmail.com>
Co-authored-by: Richard Wei <rxwei@apple.com>
The names of the private witness table accessor thunks we generate for
an opaque return type mangle the concrete conformance of the underlying
type.
If a conformance requirement of the opaque return type was witnessed by
a conditional conformance of a variadic generic type, we would crash
because of an unimplemented case in the mangler.
Fixes rdar://problem/125668798.
The deepHash() function gets called repeatedly as we descend the
node tree, which results in O(n^2) behaviour because we're traversing
entire node subtree from each node we try substitution in, in order
to calculate the hash.
Fix by adding a hash table for hashes, so that we can look up hashes
we've already computed.
This appears to yield a 26.8% saving in local tests.
rdar://125739630
Invertible protocols are currently always mangled with `Ri`, followed by
a single letter for each invertible protocol (e.g., `c` and `e` for
`Copyable` and `Escapable`, respectively), followed by the generic
parameter index. However, this requires that we extend the mangling
for any future invertible protocols, which mean they won't be
backward compatible.
Replace this mangling with one that mangles the bit # for the
invertible protocol, e.g., `Ri_` (followed by the generic parameter
index) is bit 0, which is `Copyable`. `Ri0_` (then generic parameter
index) is bit 1, which is `Escapable`. This allows us to round-trip
through mangled names for any invertible protocol, without any
knowledge of what the invertible protocol is, providing forward
compatibility. The same forward compatibility is present in all
metadata and the runtime, allowing us to add more invertible
protocols in the future without updating any of them, and also
allowing backward compatibility.
Only the demangling to human-readable strings maps the bit numbers
back to their names, and there's a fallback printing with just the bit
number when appropriate.
Also generalize the mangling a bit to allow for mangling of invertible
requirements on associated types, e.g., `S.Sequence: ~Copyable`. This
is currently unsupported by the compiler or runtime, but that may
change, and it was easy enough to finish off the mangling work for it.
This includes runtime support for instantiating transferring param/result in
function types. This is especially important since that is how we instantiate
function types like: typealias Fn = (transferring X) -> ().
rdar://123118061
