Reformatting everything now that we have `llvm` namespaces. I've
separated this from the main commit to help manage merge-conflicts and
for making it a bit easier to read the mega-patch.
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
The compiler knows (from a macro declaration) what freestanding macro
role a macro implementation is expected to implement. Pass that through
to the macro expansion code itself, rather than guessing based on the
protocol conformances of the implementation type. We already use this
approach with attached macros, so this is more of the same.
Eliminates a crash and improves diagnostics when the freestanding macro
role and its implementation are out of sync, fixing rdar://110418969.
Expand macros in the specified source file syntactically (without any
module imports, nor typechecking).
Request would look like:
```
{
key.compilerargs: [...]
key.sourcefile: <file name>
key.sourcetext: <source text> (optional)
key.expansions: [<expansion specifier>...]
}
```
`key.compilerargs` are used for getting plugins search paths. If
`key.sourcetext` is not specified, it's loaded from the file system.
Each `<expansion sepecifier>` is
```
{
key.offset: <offset>
key.modulename: <plugin module name>
key.typename: <macro typename>
key.macro_roles: [<macro role UID>...]
}
```
Clients have to provide the module and type names because that's
semantic.
Response is a `CategorizedEdits` just like (semantic) "ExpandMacro"
refactoring. But without `key.buffer_name`. Nested expnasions are not
supported at this point.
