Use the generic type lowering algorithm described in
"docs/CallingConvention.rst#physical-lowering" to map from IRGen's explosion
type to the type expected by the ABI.
Change IRGen to use the swift calling convention (swiftcc) for native swift
functions.
Use the 'swiftself' attribute on self parameters and for closures contexts.
Use the 'swifterror' parameter for swift error parameters.
Change functions in the runtime that are called as native swift functions to use
the swift calling convention.
rdar://19978563
This prevents the linker from trying to emit relative relocations to locally-defined public symbols into dynamic libraries, which gives ld.so heartache.
We have enough flag bits on function types now to warrant stashing an extra word in the metadata key alongside the arguments and results, so add one, and pack the number of arguments, function convention, and 'throws' bit in there. This lets us merge the separate metadata caches for thick/thin/block/C functions into one, saving a bit of runtime memory, and simplifying a bunch of repetitive code in the runtime and IRGen.
This also fixes a subtle bug we had where the runtime getFunctionTypeMetadata function expected the result argument to be passed in the arguments array, but IRGen was passing it as a separate argument, which would have caused function type metadata to fail to be uniqued by result type.
Swift SVN r27651
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
