[PATCH] D143501: [clang][DebugInfo] lldb: Use preferred name's type when emitting DW_AT_names

[Michael Buch via Phabricator via cfe-commits]

Michael137 added a comment.

> I'd recommend a possible long-term solution would be simplified template names (so we don't have to worry about encoding this in the `DW_AT_name` anyway) and a "DW_AT_LLVM_preferred_name" or similar attribute on a type that refers to the typedef that is the preferred name. This would generalize further than only appearing in template names - the type of a variable inside a template would also gain the beneficial naming (eg: `template<typename T> void f1(T t) { }` - as it stands, the type of the variable `t` must be `std::basic_string<char...` - but if the `DW_TAG_class_type` for `std::basic_string<char...` had this preferred-name attribute on it, then a debugger could helpfully render the type by its preferred alias instead)

That could be a neat solution. I probably asked this before, but what's the timeline with switching it on by default (if such plan is in the works at all)?

> Alternatively, I suppose, the DWARF emission could just look at the preferred name and use that as the `DW_AT_type` in all cases anyway? Avoids needing a new attribute, etc, though would be a bit quirky in its own way.

This is how I first thought of implementing it, but ran into some circular dependency quirks and started working on this patch instead. Could take a second stab at doing so if that's the preference. Would be nice to not have this behind a tuning


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