Instead of appending a character for each substitution, we now prefix the substitution with the repeat count, e.g.
AbbbbB -> A5B
The same is done for known-type substitutions, e.g.
SiSiSi -> S3i
This significantly shrinks mangled names which contain large lists of the same type, like
func foo(_ x: (Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int, Int))
rdar://problem/30707433
Officially kick SILBoxType over to be "nominal" in its layout, with generic layouts structurally parameterized only by formal types. Change SIL to lower a capture to a nongeneric box when possible, or a box capturing the enclosing generic context when necessary.
Use a syntax that declares the layout's generic parameters and fields,
followed by the generic arguments to apply to the layout:
{ var Int, let String } // A concrete box layout with a mutable Int
// and immutable String field
<T, U> { var T, let U } <Int, String> // A generic box layout,
// applied to Int and String
// arguments
Similarly to how we've always handled parameter types, we
now recursively expand tuples in result types and separately
determine a result convention for each result.
The most important code-generation change here is that
indirect results are now returned separately from each
other and from any direct results. It is generally far
better, when receiving an indirect result, to receive it
as an independent result; the caller is much more likely
to be able to directly receive the result in the address
they want to initialize, rather than having to receive it
in temporary memory and then copy parts of it into the
target.
The most important conceptual change here that clients and
producers of SIL must be aware of is the new distinction
between a SILFunctionType's *parameters* and its *argument
list*. The former is just the formal parameters, derived
purely from the parameter types of the original function;
indirect results are no longer in this list. The latter
includes the indirect result arguments; as always, all
the indirect results strictly precede the parameters.
Apply instructions and entry block arguments follow the
argument list, not the parameter list.
A relatively minor change is that there can now be multiple
direct results, each with its own result convention.
This is a minor change because I've chosen to leave
return instructions as taking a single operand and
apply instructions as producing a single result; when
the type describes multiple results, they are implicitly
bound up in a tuple. It might make sense to split these
up and allow e.g. return instructions to take a list
of operands; however, it's not clear what to do on the
caller side, and this would be a major change that can
be separated out from this already over-large patch.
Unsurprisingly, the most invasive changes here are in
SILGen; this requires substantial reworking of both call
emission and reabstraction. It also proved important
to switch several SILGen operations over to work with
RValue instead of ManagedValue, since otherwise they
would be forced to spuriously "implode" buffers.
And use project_box to get to the address value.
SILGen now generates a project_box for each alloc_box.
And IRGen re-uses the address value from the alloc_box if the operand of project_box is an alloc_box.
This lets the generated code be the same as before.
Other than that most changes of this (quite large) commit are straightforward.
Having a separate address and container value returned from alloc_stack is not really needed in SIL.
Even if they differ we have both addresses available during IRGen, because a dealloc_stack is always dominated by the corresponding alloc_stack in the same function.
Although this commit quite large, most changes are trivial. The largest non-trivial change is in IRGenSIL.
This commit is a NFC regarding the generated code. Even the generated SIL is the same (except removed #0, #1 and @local_storage).
Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
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
