This is a type that has ownership of a reference while allowing access to the
spare bits inside the pointer, but which can also safely hold an ObjC tagged pointer
reference (with no spare bits of course). It additionally blesses one
Foundation-coordinated bit with the meaning of "has swift refcounting" in order
to get a faster short-circuit to native refcounting. It supports the following
builtin operations:
- Builtin.castToBridgeObject<T>(ref: T, bits: Builtin.Word) ->
Builtin.BridgeObject
Creates a BridgeObject that contains the bitwise-OR of the bit patterns of
"ref" and "bits". It is the user's responsibility to ensure "bits" doesn't
interfere with the reference identity of the resulting value. In other words,
it is undefined behavior unless:
castReferenceFromBridgeObject(castToBridgeObject(ref, bits)) === ref
This means "bits" must be zero if "ref" is a tagged pointer. If "ref" is a real
object pointer, "bits" must not have any non-spare bits set (unless they're
already set in the pointer value). The native discriminator bit may only be set
if the object is Swift-refcounted.
- Builtin.castReferenceFromBridgeObject<T>(bo: Builtin.BridgeObject) -> T
Extracts the reference from a BridgeObject.
- Builtin.castBitPatternFromBridgeObject(bo: Builtin.BridgeObject) -> Builtin.Word
Presents the bit pattern of a BridgeObject as a Word.
BridgeObject's bits are set up as follows on the various platforms:
i386, armv7:
No ObjC tagged pointers
Swift native refcounting flag bit: 0x0000_0001
Other available spare bits: 0x0000_0002
x86_64:
Reserved for ObjC tagged pointers: 0x8000_0000_0000_0001
Swift native refcounting flag bit: 0x0000_0000_0000_0002
Other available spare bits: 0x7F00_0000_0000_0004
arm64:
Reserved for ObjC tagged pointers: 0x8000_0000_0000_0000
Swift native refcounting flag bit: 0x4000_0000_0000_0000
Other available spare bits: 0x3F00_0000_0000_0007
TODO: BridgeObject doesn't present any extra inhabitants. It ought to at least provide null as an extra inhabitant for Optional.
Swift SVN r22880
And in IRGen, fix up pointer cast codegen to work with types that explode to single scalars while being stored in named structs. Fixes rdar://problem/18604262
Swift SVN r22671
Now the SILLinkage for functions and global variables is according to the swift visibility (private, internal or public).
In addition, the fact whether a function or global variable is considered as fragile, is kept in a separate flag at SIL level.
Previously the linkage was used for this (e.g. no inlining of less visible functions to more visible functions). But it had no effect,
because everything was public anyway.
For now this isFragile-flag is set for public transparent functions and for everything if a module is compiled with -sil-serialize-all,
i.e. for the stdlib.
For details see <rdar://problem/18201785> Set SILLinkage correctly and better handling of fragile functions.
The benefits of this change are:
*) Enable to eliminate unused private and internal functions
*) It should be possible now to use private in the stdlib
*) The symbol linkage is as one would expect (previously almost all symbols were public).
More details:
Specializations from fragile functions (e.g. from the stdlib) now get linkonce_odr,default
linkage instead of linkonce_odr,hidden, i.e. they have public visibility.
The reason is: if such a function is called from another fragile function (in the same module),
then it has to be visible from a third module, in case the fragile caller is inlined but not
the specialized function.
I had to update lots of test files, because many CHECK-LABEL lines include the linkage, which has changed.
The -sil-serialize-all option is now handled at SILGen and not at the Serializer.
This means that test files in sil format which are compiled with -sil-serialize-all
must have the [fragile] attribute set for all functions and globals.
The -disable-access-control option doesn't help anymore if the accessed module is not compiled
with -sil-serialize-all, because the linker will complain about unresolved symbols.
A final note: I tried to consider all the implications of this change, but it's not a low-risk change.
If you have any comments, please let me know.
Swift SVN r22215
Any single-refcounted-pointer type can be cast from a raw pointer. Also generalize unchecked_ref_cast to cast among arbitrary single-refcounted-pointer types. Fixes rdar://problem/18184883.
Swift SVN r21609
It should definitely work with AnyObject, but it can also apply to any class existential by just shedding the witness tables. This lets us eliminate a bunch of unsafeBitCasts from the alimentary canals of the stdlib.
Swift SVN r21472
Replace the true/maybe state that Builtin.canBeClass was returning by a
tri-state (yes, no, maybe) allowing the optimizer to use the definite no
answer. This removes the need of the sizeof check that we had in
isClassOrObjCExistential. It also removes the need to CSE this function since
in most cases we will be able to instantiate canBeClass to yes or no (vs maybe)
at compile time.
benchmark``````````````,``baserun0``,``optrun2``,``delta,``speedup
ClassArrayGetter```````,``988.00````,``337.00```,``644.00``,````````191.7%
DeltaBlue``````````````,``2429.00```,``1927.00``,``460.00``,````````23.9%
Dictionary`````````````,``1374.00```,``1231.00``,``129.00``,````````10.9%
Havlak`````````````````,``1079.00```,``911.00```,``124.00``,````````13.7%
Rectangles`````````````,``924.00````,``541.00```,``379.00``,````````70.1%
radar://16823238
Swift SVN r21331
We were already effectively doing this everywhere /except/ when building
the standard library (which used -O2), so just use the model we want going
forward.
Swift SVN r20455
Add PrintForSIL in PrintOptions
1> for NameAliasType, we print getSinglyDesugaredType()
I attempted another option: set FullyQualifiedTypes of PrintOptions, but that
will print xxx.Type.xxx and Parser can’t handle it.
2> for Self, we print @sil_self
We also work around parsing:
sil_witness_table _CocoaArrayType: _CocoaArrayType
sil_vtable uses internal classes in stdlib, so we use lookupTopDecl instead
of lookupValue when parsing sil_vtable, to find internal classes.
Fix rdar://17261925 rdar://17295316 rdar://17046276 rdar://17579890
Swift SVN r20070
This only tackles the protocol case (<rdar://problem/17510790>); it
does not yet generalize to an arbitrary "class" requirement on either
existentials or generics.
Swift SVN r19896
SILGen lowers this to unchecked_trivial_bit_cast or unchecked_ref_bit_cast based on the semantics of the input and output types, raising an unsupported error if one of the types are address-only.
Swift SVN r19058
