Also, disallow creating Modules and FileUnits on the stack. They must always
live as long as the ASTContext.
<rdar://problem/15596964>
Swift SVN r13671
This completes the FileUnit refactoring. A module consists of multiple
FileUnits, which provide decls from various file-like sources. I say
"file-like" because the Builtin module is implemented with a single
BuiltinUnit, and imported Clang modules are just a single FileUnit source
within a module.
Most modules, therefore, contain a single file unit; only the main module
will contain multiple source files (and eventually partial AST files).
The term "translation unit" has been scrubbed from the project. To refer
to the context of declarations outside of any other declarations, use
"top-level" or "module scope". To refer to a .swift file or its DeclContext,
use "source file". To refer to a single unit of compilation, use "module",
since the model is that an entire module will be compiled with a single
driver call. (It will still be possible to compile a single source file
through the direct-to-frontend interface, but only in the context of the
whole module.)
Swift SVN r10837
Part of the FileUnit restructuring. A Clang module (whether from a framework
or a simple collection of headers) is now imported as a TranslationUnit
containing a single ClangModuleUnit.
One wrinkle in all this is that Swift very much wants to do searches on a
per-module basis, but Clang can only do lookups across the entire
TranslationUnit. Unless and until we get a better way to deal with this,
we're stuck with an inefficiency here. Previously, we used to hack around
this by ignoring the "per-module" bit and only performing one lookup into
all Clang modules, but that's not actually correct with respect to visibility.
Now, we're just taking the filtering hit for looking up a particular name,
and caching the results when we look up everything (for code completion).
This isn't ideal, but it doesn't seem to be costing too much in performance,
at least not right now, and it means we can get visibility correct.
In the future, it might make sense to include a ClangModuleUnit alongside a
SerializedASTFile for adapter modules, rather than having two separate
modules with the same name. I haven't really thought through this yet, though.
Swift SVN r10834
Each one has a different kind of lookup cache anyway, and there's no real
reason to have them share storage at the cost of type-safety.
Swift SVN r9242
docs/Resilience.rst describes the notion of a resilience component:
if the current source file is in the same component as a module being
used, it can use fragile access for everything in the other module,
with the assumption that everything in a component will always be
recompiled together.
However, nothing is actually using this today, and the interface we
have is probably not what we'll want in 2.0, when we actually implement
resilience.
Swift SVN r9174
This handles both Clang’s transitive inclusion and the use of
"adapter modules" to augment the Clang modules (e.g. Foundation.swift),
at the cost of a bit more memory (used to wrap all the Clang modules
in ClangModule objects). This is paving the way for making Sema
independent of ClangImporter.
Swift SVN r6698
This makes it very clear who is depending on special behavior at the
module level. Doing isa<ClangModule> now requires a header import; anything
more requires actually linking against the ClangImporter library.
If the current source file really can't import ClangModule.h, it can
still fall back to checking against the DeclContext's getContextKind()
(and indeed AST currently does in a few places).
Swift SVN r6695
