[cfe-dev] Parsing field types from ClassTemplateSpecializationDecl

[Marko Pintera via cfe-dev]

You are right, embarrassingly my test case was incorrectly written, it
works now. Thank you.

On 19 July 2017 at 16:56, Raphael Isemann <teemperor at gmail.com> wrote:

> Not sure if I understand correctly, but you specialize your template
> without any fields in your example.
>
> What you want to do is I think:
>
>    template class Foo<float>;
>
> which yields the correct result for me:
>
> teemperor at ftlserver ~/test> cat test.cpp
> template <class T>
> class Foo
> {
>        T bar;
> };
>
> template class Foo<float>;
> teemperor at ftlserver ~/test> clang++ -cc1 -fcolor-diagnostics -ast-dump
> -x c++ test.cpp
> TranslationUnitDecl 0x5578e347d9a0 <<invalid sloc>> <invalid sloc>
> |-TypedefDecl 0x5578e347df30 <<invalid sloc>> <invalid sloc> implicit
> __int128_t '__int128'
> | `-BuiltinType 0x5578e347dc10 '__int128'
> |-TypedefDecl 0x5578e347df98 <<invalid sloc>> <invalid sloc> implicit
> __uint128_t 'unsigned __int128'
> | `-BuiltinType 0x5578e347dc30 'unsigned __int128'
> |-TypedefDecl 0x5578e347e2d8 <<invalid sloc>> <invalid sloc> implicit
> __NSConstantString 'struct __NSConstantString_tag'
> | `-RecordType 0x5578e347e080 'struct __NSConstantString_tag'
> |   `-CXXRecord 0x5578e347dfe8 '__NSConstantString_tag'
> |-TypedefDecl 0x5578e347e370 <<invalid sloc>> <invalid sloc> implicit
> __builtin_ms_va_list 'char *'
> | `-PointerType 0x5578e347e330 'char *'
> |   `-BuiltinType 0x5578e347da30 'char'
> |-TypedefDecl 0x5578e34b2320 <<invalid sloc>> <invalid sloc> implicit
> __builtin_va_list 'struct __va_list_tag [1]'
> | `-ConstantArrayType 0x5578e347e650 'struct __va_list_tag [1]' 1
> |   `-RecordType 0x5578e347e460 'struct __va_list_tag'
> |     `-CXXRecord 0x5578e347e3c0 '__va_list_tag'
> |-ClassTemplateDecl 0x5578e34b24b8 <test.cpp:1:1, line:5:1> line:2:7 Foo
> | |-TemplateTypeParmDecl 0x5578e34b2370 <line:1:11, col:17> col:17
> referenced class T
> | |-CXXRecordDecl 0x5578e34b2420 <line:2:1, line:5:1> line:2:7 class
> Foo definition
> | | |-CXXRecordDecl 0x5578e34b2728 <col:1, col:7> col:7 implicit class Foo
> | | `-FieldDecl 0x5578e34b27d0 <line:4:2, col:4> col:4 bar 'T'
> | `-ClassTemplateSpecialization 0x5578e34b2850 'Foo'
> `-ClassTemplateSpecializationDecl 0x5578e34b2850 <line:7:1, col:25>
> col:16 class Foo definition
>  |-TemplateArgument type 'float'
>  |-CXXRecordDecl 0x5578e34b2a48 prev 0x5578e34b2850 <line:2:1, col:7>
> col:7 implicit class Foo
>  `-FieldDecl 0x5578e34b2b18 <line:4:2, col:4> col:4 bar 'float':'float'
>
>
> - Raphael
>
> 2017-07-19 16:30 GMT+02:00 Marko Pintera via cfe-dev <
> cfe-dev at lists.llvm.org>:
> > Hello,
> >
> > I'm trying to parse fields of an explicitly instantiated template, like
> > this:
> > ~~~
> > template <class T>
> > class Foo
> > {
> > T bar;
> > };
> >
> > template<> class Foo<float>;
> > ~~~
> >
> > In the example above, I'd like to know that "Foo<float>" has a field
> "bar"
> > of type "float".
> >
> > I am able to access "ClassTemplateSpecializationDecl" of "Foo<float>",
> but
> > it reports no fields. It does contain a list of template arguments (a
> > "float" for the specific example above), but since there are no fields I
> am
> > unsure how to interpret them.
> >
> > I can also access "CXXRecordDecl" of "Foo<T>" by calling
> > "ClassTemplateSpecializationDecl::getSpecializedTemplate()->
> GetTemplatedDecl()".
> > This does report the "bar" field, but I do not appear to have information
> > about its actual type from the explicit instantiation.
> >
> > How can I learn the type of "bar" in an explicit instantiation of
> "Foo<T>"?
> >
> > Thanks!
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >
>
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