Jean-Michaël Celerier via llvm-dev
2020-Oct-05 07:44 UTC
[llvm-dev] Clang API: any way to use a virtual filesystem ?
Hello, I am shipping my app (https://ossia.io) with an embedded clang to allow people to write extensions in C++ at run-time. For that to work I also ship a SDK with all the required headers, libc++, etc... which is downloaded & extracted in some folder. Problem is: while on my linux dev. machine this operation is fast, apparently on Windows and mac extracting a .zip with a few thousand files takes the better part of a decade - just downloading the sdk.zip makes my Safari get stuck for ten minutes as this idiot tries to extract it itself (see the sdk files there: https://github.com/ossia/score/releases/tag/v3.0.0-a14-1). My question is: is it possible to hook something in clang to allow it to go look for files inside a virtual file system à la https://github.com/yevgeniy-logachev/vfspp for instance ? This way I would only download the zip, not extract it, and it'd be just opened in ram when needed. Or does it necessarily go through fopen() for includes right now ? Kind regards, Jean-Michaël -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20201005/177907f5/attachment.html>
Jacob Carlborg via llvm-dev
2020-Oct-05 16:00 UTC
[llvm-dev] Clang API: any way to use a virtual filesystem ?
On 2020-10-05 09:44, Jean-Michaël Celerier via llvm-dev wrote:> My question is: is it possible to hook something in clang to allow it to > go look for files inside a virtual file system à la > https://github.com/yevgeniy-logachev/vfspp for instance ? This way I > would only download the zip, not extract it, and it'd be just opened in > ram when needed. > Or does it necessarily go through fopen() for includes right now ?I have a tool where I use libclang (the C API). For the internal headers, I've embedded those inside the executable, to avoid the need to ship them separately or have the users to install them. What I do is for each header file I create a `CXUnsavedFile` [1]. Then I can pass that to `clang_parseTranslationUnit` when parsing the source files. `CXUnsavedFile` expects the filename and the content of the file. If you can get that, you should be able to use the same approach. If you're using the C++ API, you can have a look at the implementation of `clang_parseTranslationUnit` to see how to do the same using the C++ API. [1] https://clang.llvm.org/doxygen/structCXUnsavedFile.html [2] https://clang.llvm.org/doxygen/group__CINDEX__TRANSLATION__UNIT.html#ga2baf83f8c3299788234c8bce55e4472e -- /Jacob Carlborg
Jean-Michaël Celerier via llvm-dev
2020-Oct-05 19:32 UTC
[llvm-dev] Clang API: any way to use a virtual filesystem ?
Thanks, those are very good starting points ! I'll try to make it work and report if it does if that can be useful to someone else. All the best, Jean-Michaël ------- Jean-Michaël Celerier http://www.jcelerier.name On Mon, Oct 5, 2020 at 6:01 PM Jacob Carlborg via llvm-dev < llvm-dev at lists.llvm.org> wrote:> On 2020-10-05 09:44, Jean-Michaël Celerier via llvm-dev wrote: > > > My question is: is it possible to hook something in clang to allow it to > > go look for files inside a virtual file system à la > > https://github.com/yevgeniy-logachev/vfspp for instance ? This way I > > would only download the zip, not extract it, and it'd be just opened in > > ram when needed. > > Or does it necessarily go through fopen() for includes right now ? > > I have a tool where I use libclang (the C API). For the internal > headers, I've embedded those inside the executable, to avoid the need to > ship them separately or have the users to install them. > > What I do is for each header file I create a `CXUnsavedFile` [1]. Then > I can pass that to `clang_parseTranslationUnit` when parsing the source > files. > > `CXUnsavedFile` expects the filename and the content of the file. If you > can get that, you should be able to use the same approach. > > If you're using the C++ API, you can have a look at the implementation > of `clang_parseTranslationUnit` to see how to do the same using the C++ > API. > > [1] https://clang.llvm.org/doxygen/structCXUnsavedFile.html > [2] > > https://clang.llvm.org/doxygen/group__CINDEX__TRANSLATION__UNIT.html#ga2baf83f8c3299788234c8bce55e4472e > > -- > /Jacob Carlborg > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20201005/520acca2/attachment.html>
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