shchenz added a comment. In D100630#2749594 <https://reviews.llvm.org/D100630#2749594>, @dblaikie wrote:
> In D100630#2749550 <https://reviews.llvm.org/D100630#2749550>, @shchenz wrote: > >> In D100630#2748899 <https://reviews.llvm.org/D100630#2748899>, @dblaikie >> wrote: >> >>> Does this cause duplicate DW_TAG_reference_types in the output, if the >>> input IR Has both DW_TAG_reference_type and DW_TAG_rvalue_reference_types? >> >> Yes, it will cause such issue in theory. I can not cook a case that has a >> DW_TAG_reference_type to a DW_TAG_rvalue_reference_types or has a >> DW_TAG_rvalue_reference_types to a DW_TAG_reference_type for now. Is there >> such usage that we both be rvalue-reference and lvalue-reference to a basic >> type? > > Ah, I was less thinking of a case of an rvalue reference and a normal > reference in the same chain - I was thinking more about two unrelated > reference types. > > Try some code like: > > void f1(int &&x, int &y) { > } > > I'm guessing without this change - you get 'x's type pointing to the > rvalue_reference_type, 'y's type pointing to the reference_type, and both of > those pointing to the 'int' DW_TAG_basic_type. > > But with this change I'm worried you'll get two copies of the > DW_TAG_reference_type - one that replaces the rvalue reference, and then the > real one. Instead you should get one copy that both 'x' and 'y' refer to, I > think. Hmm, yeah, indeed, a duplicated `DW_TAG_reference_type` is generated. 0x00000069: DW_TAG_reference_type DW_AT_type (0x0000006e "int") 0x0000006e: DW_TAG_base_type DW_AT_name ("int") DW_AT_encoding (DW_ATE_signed) DW_AT_byte_size (0x04) 0x00000075: DW_TAG_reference_type DW_AT_type (0x0000006e "int") I think rather than fixing the duplicated `DW_TAG_reference_type` in the backend, maybe it is better to fix this strict DWARF issue in the FE like the fix in the previous patch https://reviews.llvm.org/D100630?id=338755 What do you think? @dblaikie Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D100630/new/ https://reviews.llvm.org/D100630 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
