[cfe-commits] [PATCH] #import directive in MS compatibility mode

[Francois Pichet]

On Wed, Mar 14, 2012 at 12:15 PM, Douglas Gregor <dgregor at apple.com> wrote:
>
> On Mar 12, 2012, at 4:10 PM, Aaron Ballman wrote:
>
>> MSVC uses the #import directive in a far different way than the
>> language extension clang supports.  Instead of including the target
>> into the source, it parses a type library and generates C++ classes
>> from the definitions.  This difference in behavior is large enough
>> that we should be warning users in MS compatibility mode so they can
>> understand what's happening.
>>
>> This patch addresses PR 10727.
>
>
> Given that the subject of an MSVC-style #import is likely to be a binary file, I think it would be better to simply warn that we are ignoring the #import directly entirely, rather than going through HandleIncludeDirective. Also, can you perhaps make

Actually, MSVC #import will generate 2 header files from the typelib
and then include them. I think generating *.h from COM typelib is
outside the scope of clang but we could somehow assume that the .h are
already pregenerated and try to include them.

That would make it possible to compile a COM project with clang if the
project has already been compiled with MSVC first. (to get the .h
generated).