On Windows/AArch64, a different register is used between when an
arugment is both inreg and sret (X0 or X1) and when it is just sret
(X8) as the following comment indicates:
46fe36a429/llvm/lib/Target/AArch64/AArch64CallingConvention.td (L42)
```
// In AAPCS, an SRet is passed in X8, not X0 like a normal pointer parameter.
// However, on windows, in some circumstances, the SRet is passed in X0 or X1
// instead. The presence of the inreg attribute indicates that SRet is
// passed in the alternative register (X0 or X1), not X8:
// - X0 for non-instance methods.
// - X1 for instance methods.
// The "sret" attribute identifies indirect returns.
// The "inreg" attribute identifies non-aggregate types.
// The position of the "sret" attribute identifies instance/non-instance
// methods.
// "sret" on argument 0 means non-instance methods.
// "sret" on argument 1 means instance methods.
CCIfInReg<CCIfType<[i64],
CCIfSRet<CCIfType<[i64], CCAssignToReg<[X0, X1]>>>>>,
CCIfSRet<CCIfType<[i64], CCAssignToReg<[X8]>>>,
```
So missing/dropping inreg can cause a codegen bug.
This is a partial fix for #74866
Adds sections `__TEXT,__swift_as_entry`, and `__TEXT,__swift_as_ret` that
contain relative pointers to async functlets modelling async function entries,
and function returns, respectively.
Emission of the sections can be trigger with the frontend option
`-Xfrontend -enable-async-frame-push-pop-metadata`.
This is done by:
* IRGen adding a `async_entry` function attribute to async functions.
* LLVM's coroutine splitting identifying continuation funclets that
model the return from an async function call by adding the function
attribute `async_ret`. (see #llvm-project/pull/9204)
* An LLVM pass that keys off these two function attribute and emits the
metadata into the above mention sections.
rdar://134460666
This fixes a runtime crash that occurs when a pointer to a foreign
reference type is passed to objc_retainAutoreleasedReturnValue.
This reverts 335cec0e8d.
rdar://117353222
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.
Conflicts:
- `test/Interop/Cxx/class/method/methods-this-and-indirect-return-irgen-itanium.swift`
previously fixed on rebranch, now fixed on main (slightly differently).
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
