[PATCH] D134330: [Docs] [HLSL] Add note about PCH support

[Chris Bieneman via Phabricator via cfe-commits]

beanz added inline comments.


================
Comment at: clang/docs/HLSL/HLSLSupport.rst:98
+``HLSLExternalSemaSource`` will create new decls and use the old decls as
+argument for setPreviousDecl.
+
----------------
We can probably generalize this to something like:
```
When precompiled headers are used compiling HLSL, the ``ExternalSemaSource``
will be a ``MultiplexExternalSemaSource`` which include both the ``ASTReader``
and ``HLSLExternalSemaSource``. For Built-in declarations that are  already
completed in the serialized AST, the ``HLSLExternalSemaSource`` will reuse the
existing declarations and not introduce new declarations. If the built-in types
are not completed in the serialized AST, the ``HLSLExternalSemaSource`` will
create new declarations and connect the de-serialized decls as the previous
declaration.
```


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D134330