This includes the reading half of BCRecordLayout metaprogramming, and
then a fairly straightforward deserialize-and-cache implementation in
ModuleFile. Once again, this is based on Clang's module implementation:
decls and types are referred to by an ID, which is used as an index into
an array, which contains offsets to the definitions of the decl/type in
the "decls-and-types" block in the serialized module.
In order to test the feature, the code is currently eagerly deserializing
all declarations. This will be partially fixed in the next commit.
Swift SVN r5324
Clang modules have a clever way to share decl and type IDs, by saying
"this range of IDs comes from this other module". Swift modules have to
be resilient, however, and so this is not a viable solution.
We still use 0 as a special ID for null decls and types, when applicable.
Swift SVN r5323
...but don't do anything with them yet. This does check that they're being
correctly serialized, though.
This introduces a new ADT, PointerIntUnion, which like PointerUnion is an
efficient variant type using the lowest bit of data as a discriminator.
By default, the union can store any pointer-bits-minus-one-sized integer,
but both the integer type and the underlying storage type can be
customized.
Swift SVN r5321
The bringup hack, again, is to just process the module source files as a
TranslationUnit if the module doesn't accurately represent the original
source. Currently this happens if the module is not empty, or if it imports
/anything/, since we don't actually serialize anything yet.
This also cleans up the decl/type serialization skeleton a bit.
Swift SVN r5238
Like Clang, ModuleFile contains state about reading the serialized module,
while SerializedModuleLoader takes the place of ASTReader in tracking
cross-module data. I'm diverging from Clang's architecture a bit here by
pushing the actual deserialization logic into ModuleFile.
No functionality change.
Swift SVN r5174
