martong added a comment. In D59485#1439390 <https://reviews.llvm.org/D59485#1439390>, @teemperor wrote:
> > Well, I still don't understand how LLDB synthesis the AST. > > So you have a C++ module in a .pcm file. This means you could create an > > AST from that with ASTReader from it's .clang_ast section, right? In that > > case the AST should be complete with all type information. If this was the > > case then I don't see why it is not possible to use clang::ASTImporter to > > import templates and specializations, since we do exactly that in CTU. > > > > Or do you guys create the AST from the debug info, from the .debug_info > > section of .pcm module file? And this is why AST is incomplete? I've got > > this from > > https://youtu.be/EgkZ8PTNSHQ?list=PL85Cf-ok7HpppFWlp2wX_-A1dkyFVlaEB&t=1565 > > If this is the case, then comes my naiive quiestion: Why don't you use the > > ASTReader? > > There are no C++ modules involved in our use case beside the generic `std` > module. No user-written code is read from a module and we don't have any PCM > file beside the `std` module we build for the expression evaluator. > > We use the ASTReader to directly read the `std` module contents into the > expression evaluation ASTContext, but this doesn't give us the decls for the > instantiations the user has made (e.g. `std::vector<Foo>`). We only have > these user instantiations in the 'normal' debug info where we have a rather > minimal AST (again, no modules are not involved in building this debug info > AST). The `InternalImport` in the LLDB patch just stitches the module AST and > the debug info AST together when we import something that we also have (in > better quality from the C++ module) in the target ASTContext. Thank you for the explanation. Now I understand you directly create specializations from the std module and intercept the import to avoid importing broken specializations from the debug info, this makes sense. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D59485/new/ https://reviews.llvm.org/D59485 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
