Don't project every value witness from the metadata every time we need one; this wastes code size in a way LLVM can't really optimize since it doesn't know the metadata is immutable. The code size wins on the standard library are disappointingly small (stdlib only shrinks by 4KB), but this makes generic IR a lot more compact and easier to read.
Swift SVN r28095
We've had a rash of bugs due to inconsistencies between how IRGen and the runtime think types are laid out. Add a '-verify-type-layout' mode to the frontend that causes IRGen to emit a bunch of code that compares its static assumptions against what the runtime value witness does.
Swift SVN r24918
initializeBufferWithTakeOfBuffer value witness.
Attempt to use initializeBufferWithTakeOfBuffer in
some appropriate places.
There are some changes enabled by this which are
coming in a follow-up patch.
Swift SVN r20741
Add Builtin.destroyArray, .copyArray, .takeArrayFrontToBack, and .takeArrayBackToFront, which perform bulk destroy/copy/take operations using memcpy/memmove, a loop, or a generic value witness.
Swift SVN r17009
Add value witnesses for destroyArray, initializeArrayWithCopy, and initializeArrayWithTake{FrontToBack,BackToFront}, and fill out the runtime value witness table implementations. Stub out the IRGen ones for now.
Swift SVN r16772
If a single-payload union doesn't use up all of its payload's extra inhabitants, it can claim the remaining ones as its own. While we're here, specialize the extra inhabitants implementation for no-payload unions to generously (and more efficiently) give out all integer values within its storage type above the largest discriminator as extra inhabitants, instead of relying entirely on the spare bits mask.
Swift SVN r8470
These value witness table entries will be conditionally available for types that support specialized union representation through extra inhabitants and/or spare bits and for union value witnesses:
- storeExtraInhabitant, to store an extra inhabitant representation;
- getExtraInhabitantIndex, to recognize an extra inhabitant representation;
- getUnionTag, to get a union's discriminator; and
- inplaceProjectUnionData, to extract the value in place from a union.
This just sets up the enumerators and related IR types and mangling; nothing emits these witnesses yet.
Swift SVN r7234
The value witnesses are always available through type metadata (through an extra indirection). Saving that indirection costs 16 words (and growing!) in every witness table, and when we start instantiating conformances for generic instances, would require us to instantiate practically every generic witness table. Removing the value witnesses from the protocol witness table means we will only need to instantiate witness tables when associated types are dependent on the conforming type's type variables.
This is an ABI break, but should have no user-visible functional change.
Swift SVN r6651
Provide a lowering for the DeinitExistential instruction to deallocate the buffer in an existential container with an uninitialized value, using its deallocateBuffer witness.
Swift SVN r5623
storage in a flags word in the value witness table. Pack the
alignment into only 16 bits of this word. Optimize tuple value
witnesses based on whether they're POD and inline.
Swift SVN r5138
To be able to get the dynamic type of a generic value, the 'typeof' operation needs to be part of the value witness for the type. Add 'typeof' to the value witness table layout, and in the runtime, provide standard typeof witnesses for static, Swift class, and ObjC class values.
Swift SVN r5013
