@differentiable function is actually a triple (function, jvp, vjp). Previously normal thick function value witness table was used. As a result, for example, only function was copied, but none of differential components.
This was the cause of uninitialized memory accesses and subsequent segfaults.
Should fix now unavailable TF-1122
The new intrinsic, exposed via static functions on Task<T, Never> and
Task<T, Error> (rethrowing), begins an asynchronous context within a
synchronous caller's context. This is only available for use under the
task-to-thread concurrency model, and even then only under SPI.
Defined SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY to describe
whether the standard library will use the task-to-thread model for
concurrency. It is true only for freestanding non-Darwin stdlibs.
When it is true, SWIFT_CONCURRENCY_TASK_TO_THREAD_MODEL is defined
during stdlib compilation of both Swift and C++ sources.
Added an option to LangOptions to specify which concurrency model is
used, either standard or task-to-thread. When
SWIFT_STDLIB_TASK_TO_THREAD_MODEL_CONCURRENCY is true, the model is
specified to be task-to-thread.
The threading implementations need to include Impl.h, not just their
specific variant, to pick up the `stack_bounds` type.
Also fix a newly exposed problem with Atomic.h.
rdar://90776105
Moved all the threading code to one place. Added explicit support for
Darwin, Linux, Pthreads, C11 threads and Win32 threads, including new
implementations of Once for Linux, Pthreads, C11 and Win32.
rdar://90776105
SWIFT_STDLIB_SINGLE_THREADED_RUNTIME is too much of a blunt instrument here.
It covers both the Concurrency runtime and the rest of the runtime, but we'd
like to be able to have e.g. a single-threaded Concurrency runtime while
the rest of the runtime is still thread safe (for instance).
So: rename it to SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY and make it just
control the Concurrency runtime, then add a SWIFT_STDLIB_THREADING_PACKAGE
setting at the CMake/build-script level, which defines
SWIFT_STDLIB_THREADING_xxx where xxx depends on the chosen threading package.
This is especially useful on systems where there may be a choice of threading
package that you could use.
rdar://90776105
The threading implementations need to include Impl.h, not just their
specific variant, to pick up the `stack_bounds` type.
Also fix a newly exposed problem with Atomic.h.
rdar://90776105
Moved all the threading code to one place. Added explicit support for
Darwin, Linux, Pthreads, C11 threads and Win32 threads, including new
implementations of Once for Linux, Pthreads, C11 and Win32.
rdar://90776105
SWIFT_STDLIB_SINGLE_THREADED_RUNTIME is too much of a blunt instrument here.
It covers both the Concurrency runtime and the rest of the runtime, but we'd
like to be able to have e.g. a single-threaded Concurrency runtime while
the rest of the runtime is still thread safe (for instance).
So: rename it to SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY and make it just
control the Concurrency runtime, then add a SWIFT_STDLIB_THREADING_PACKAGE
setting at the CMake/build-script level, which defines
SWIFT_STDLIB_THREADING_xxx where xxx depends on the chosen threading package.
This is especially useful on systems where there may be a choice of threading
package that you could use.
rdar://90776105
The placement new operator is only available when `<new>` has been
included. Add the missing include to the header to allow us to get the
definition of the placement new allocator. This allows us to remove the
workaround that was there for Windows, and should hopefully repair the
Android build as well.
Thanks to @grynspan for helping identify the underlying issue!
Not all targets have a 16-byte type alignment guarantee. For the types
which are not naturally aligned, provide a type specific `operator new`
overload to ensure that we are properly aligning the type on allocation
as we run the risk of under-aligned allocations otherwise.
This should no longer be needed with C++17 and newer which do a two
phase `operator new` lookup preferring
`operator new(std::size, std::align_val_t)` if needed. The base type
would be fully pre-processed away. The empty base class optimization
should help ensure that we do not pay any extra size costs for the
alignment fixes.
As we are a C++14 codebase, we must locally implement some of the
standard type_traits utilities, namely `void_t`. We take the minimal
definition here, assuming that the compiler is up-to-date with C++14 DR
reports which fixed an issue in SFINAE. We use the SFINAE for detecting
the presence of the `operator new` overload to guide the over-alignment,
which is inherited through the new `swift::overaligned_type<>` base
type.
Annotate the known classes which request explicit alignment which is
non-pointer alignment. This list was identified by
`git grep ' alignas(.*) '`.
When SWIFT_COMPACT_ABSOLUTE_FUNCTION_POINTER is enabled, relative direct
pointers whose pointees are functions will be turned into absolute
pointer at compile-time.
`operator new` up until C++17 was alignment unaware. We use C++ types
decorated with `alignas` to enforce 16-byte alignment. This is fine on
the current platforms that we support as they are all enforcing 16-byte
alignment on allocations. However, this is not a guarantee that C++
makes. It only provides the guarantee that `operator new` will align
the memory to `__STDCPP_DEFAULT_NEW_ALIGNMENT__`. On 32-bit platforms
such as Windows i686, this value is actually 8. However, due to the
class(es) being attributed as `alignas(16)`, the default constructor
which is emitted by the compiler assumes the proper alignment will be
provided for externally and will zero the memory using the following
sequence:
~~~
xorps xmm0, xmm0
movaps xmm0, [eax]
movaps xmm0, [eax+16]
~~~
This assumes that the returned pointer is suitably aligned for XMM
operations - 16-bytes - as the attribution indicates as such. This
misalignment would cause a bus error on Linux, and more confusingly
triggers an invalid access (the equivalent of a segmentation fault)
on Windows.
Add a static assertion to identify this unintended misalignment on
allocation. This check will be meaningless post C++17 as that will use
a two-phase overload resolution for `operator new`, preferring the newly
introduced `operator new(std::size_t, std::align_val_t)` which would
suitably align the type and as such is guarded by the feature macro
`__cpp_aligned_new`.
The immediate use case is only concretely-constrained existential
types, which could use a much simpler representation, but I've
future-proofed the representation as much as I can; thus, the
requirement signature can have arbitrary parameters and
requirements, and the type can have an arbitrary type as the
sub-expression. The latter is also necessary for existential
metatypes.
The chief implementation complexity here is that we must be able
to agree on the identity of an existential type that might be
produced by substitution. Thus, for example, `any P<T>` when
`T == Int` must resolve to the same type metadata as
`any P<Int>`. To handle this, we identify the "shape" of the
existential type, consisting of those parts which cannot possibly
be the result of substitution, and then abstract the substitutable
"holes" as an application of a generalization signature. That
algorithm will come in a later patch; this patch just represents
it.
Uniquing existential shapes from the requirements would be quite
complex because of all the symbolic mangled names they use.
This is particularly true because it's not reasonable to require
translation units to agree about what portions they mangle vs.
reference symbolically. Instead, we expect the compiler to do
a cryptographic hash of a mangling of the shape, then use that
as the unique key identifying the shape.
This is just the core representation and runtime interface; other
parts of the runtime, such as dynamic casting and demangling
support, will come later.
The demangling library can't use the error handling from the main runtime
because it isn't always linked with it. However, it's useful to have
some error handling, and in particular to be able to get data into the
crash logs.
This is complicated because of the way the demangling library gets used,
the upshot of which is that I've had to add a second object library just
for libswiftCore's use, so that the demangler will use the runtime's
error handling functions when present, and fall back on its own when
they aren't.
rdar://89139049
This adds a new reflection record type carrying spare bit information for multi-payload enums.
The compiler includes this for any type that might need it in order to accurately reflect the contents of the enum. The RemoteMirror library will use this if present to determine how to project the contents of the enum. If not present (for example, in older binaries), the RemoteMirror library falls back on an internal calculation of the spare bitmask.
A few notes:
* The internal calculation is not perfect. In particular, it does not support MPEs that contain other enums (e.g., optionals). It should accurately refuse to project any MPE that it does not correctly support.
* The new reflection field is designed to be expandable; this might someday avoid the need for a new section.
Resolves rdar://61158214
