[cfe-dev] FunctionProtoType is changed during include expansion

David Blaikie via cfe-dev cfe-dev at lists.llvm.org
Mon Dec 2 09:57:12 PST 2019

perhaps a smaller reproducer would be useful for this discussion? (so we
could see the specific code, rather than a description of it or the entire
libc++ test, etc)

On Mon, Dec 2, 2019 at 12:27 PM Gábor Márton via cfe-dev <
cfe-dev at lists.llvm.org> wrote:

> Hi,
> I am puzzling with the following phenomenon:
> When I compile a source file normally (i.e. -c) then a given lambda's
> signature is `operator() 'int_type (long) const'` where int_type is a
> TypeAlias. I.e. the return type is a TypedefType.
> Now, when I compile the same source file with -E, then the signature is
> changed to the canonical type: `operator() 'long (long) const'`. I.e. the
> return type is no longer a TypedefType.
> This happens also when I use `-E -frewrite-includes`.
> Do you guys have any insights on this? What happens during include
> expansion so that the parser changes some internal state?
> Thanks,
> Gabor
> ...
> Why this is a problem to me? Because I can't write tests that are
> self-contained, the problematic AST with the TypedefType return type comes
> up only when we include some files.
> For your interest, if you want to reproduce it, you can do that on
> llvm-project/master:
> 1) Enable libcxx, libcxxabi
> 2) ninja cxx
> 3) ninja -v
> projects/libcxx/src/CMakeFiles/cxx_static.dir/filesystem/directory_iterator.cpp.o
>     - grab the output and attach -E (and -frewrite-includes)
> 4) ./bin/clang-check -p . libcxx/src/filesystem/directory_iterator.cpp
> -ast-dump -ast-dump-filter "posix_utimes" | ag "CXXMethodDecl.*int_type"
>    - gives -CXXMethodDecl 0x3007ec0 <col:30, line:400:3> line:396:18 used
> operator() 'int_type (long) const' inline
> 5) ./bin/clang -x c++ directory_iterator.cpp.E -fsyntax-only -Xclang
> -ast-dump -Xclang -ast-dump-filter -Xclang posix_utimes | ag
> "CXXMethodDecl.*operator"
> 6) -CXXMethodDecl 0x31c6ad0 <col:30, line:400:3> line:396:18 used
> operator() 'long (long) const' inline
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20191202/9d247fe5/attachment.html>

More information about the cfe-dev mailing list