Previously we were using the same set of conditions
for serializing as for swiftdoc, so excluded them.
However it's reasonable to have them in the
swiftsourceinfo.
After setting up the .swiftsourceinfo file, this patch starts to actually serialize
and de-serialize source locations for declaration. The binary format of .swiftsourceinfo
currently contains these three records:
BasicDeclLocs: a hash table mapping from a USR ID to a list of basic source locations. The USR id
could be retrieved from the following DeclUSRs record using an actual decl USR. The basic source locations
include a file ID and the results from Decl::getLoc(), ValueDecl::getNameLoc(), Decl::getStartLoc() and Decl::getEndLoc().
The file ID could be used to retrieve the actual file name from the following SourceFilePaths record.
Each location is encoded as a line:column pair.
DeclUSRS: a hash table mapping from USR to a USR ID used by location records.
SourceFilePaths: a hash table mapping from a file ID to actual file name.
BasicDeclLocs should be sufficient for most diagnostic cases. If additional source locations
are needed, we could always add new source location records without breaking the backward compatibility.
When de-serializing the source location from a module-imported decl, we calculate its USR, retrieve the USR ID
from the DeclUSRS record, and use the USR ID to look up the basic location list in the BasicDeclLocs record.
For more details about .swiftsourceinfo file: https://forums.swift.org/t/proposal-emitting-source-information-file-during-compilation
In most cases this means adding @public to things that get serialized;
in a few cases it means using a modern public stdlib API instead of
a legacy thing I was trying to keep @internal.
Swift SVN r19350
The driver infers the filename from the module file by replacing the extension,
and passes the explicit path to the swiftdoc file to the frontend. But there
is no option in the driver to control emission of swiftdoc (it is always
emitted, and name is always inferred from the swiftmodule name).
The swiftdoc file consists of a single table that maps USRs to {brief comment,
raw comment}. In order to look up a comment for decl we generate the USR
first. We hope that the performance hit will not be that bad, because most
declarations come from Clang. The advantage of this design is that the
swiftdoc file is not locked to the swiftmodule file, and can be updated,
replaced, and even localized.
Swift SVN r14914
