This flag is required for performing the propagation of global and static "let" values into their uses.
Let variables have now a [let] attribute in the SIL textual form.
Swift SVN r30153
This is necessary for correctly dealing with non-standard
ownership conventions in secondary positions, and it should
also help with non-injective type imports (like BOOL/_Bool).
But right now we aren't doing much with it.
Swift SVN r26954
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
It is defaulted to nullptr. When it is set, we increment the SILFunction's
ref count to keep it alive.
It will be used in followon patches for globals that can be statically
initialized.
Swift SVN r21983
We add two more fields to SILGlobalVariable: a VarDecl and a flag to see if this
is a declaration. VarDecl is mainly used for debugger support, it is also used
to check if the variable is weak imported.
We also modify the serializer to serialize the extra two fields.
Swift SVN r21883
In general, this forces SILGen and IRGen code that's grabbing
a declaration to state whether it's doing so to define it.
Change SIL serialization to serialize the linkage of functions
and global variables, which means also serializing declarations.
Change the deserializer to use this stored linkage, even when
only deserializing a declaration, and to call a callback to
inform the client that it has deserialized a new entity.
Take advantage of that callback in the linking pass to alter
the deserialized linkage as appropriate for the fact that we
imported the declaration. This computation should really take
advantage of the relationship between modules, but currently
it does not.
Swift SVN r12090
Like GlobalAddrInst, but for SILGlobalVariables. These would become the same instruction when SILGlobalVariable can replace AST-level global references.
Swift SVN r10510
This will let us control linkage and emit new variables independent of the AST in SILGen. In particular, for lazy global initialization, we need to emit a unique internal once predicate for every top-level pattern binding. Switching everything over is a bit much to reengineer all at once, so for now, it can coexist with the globals map that is already there.
Swift SVN r10509
