[Lldb-commits] [PATCH] D81471: [lldb] Add support for using integral const static data members in the expression evaluator

[Pavel Labath via Phabricator via lldb-commits]

labath added a comment.

My only complaint is about the restriction in CanTakeAddressOfLValue. It seems arbitrary. There's anything in C++ or DWARF that would prevent us from having constant-valued variables of class types. It's just that clang/llvm does not know how to emit the DW_AT_const_value for such variables (yet). Gcc does not seem to have that problem (it happily emits a block form for those). So, it feels to me this is just kicking the can down the road, and we will sooner or later need to come up with a better story for this.

I guess the condition we really want to express here is "does this expression refer to a constexpr variable (ideally one without a location)"? And the problem is that clang does not give us the means to detect that?

Is that really the case? Would it maybe be possible to use some c++ magic to get clang to do that for us. Write something like `if constexpr (__builtin_constant_p(user_expression)) do_something_rvalue_like(); else assume_regular_lvalue();` ?


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https://reviews.llvm.org/D81471