build_enum_variant_struct_type_di_node in rustc_codegen_llvm::debuginfo::metadata::enums - Rust
Description: Build the debuginfo node for the struct type describing a single variant of an enum.

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## build_enum_variant_struct_type_di_node

# Function build_enum_variant_struct_type_di_node

Source

    fn build_enum_variant_struct_type_di_node<'ll, 'tcx>(
        cx: &GenericCx<'ll, FullCx<'ll, 'tcx>>,
        enum_type_and_layout: TyAndLayout<'tcx>,
        enum_type_di_node: &'ll Metadata,
        variant_index: VariantIdx,
        variant_def: &VariantDef,
        variant_layout: TyAndLayout<'tcx>,
        di_flags: DIFlags,
    ) -> &'ll Metadata

Expand description

Build the debuginfo node for the struct type describing a single variant of an enum.

          DW_TAG_structure_type              (top-level type for enum)
            DW_TAG_variant_part              (variant part)
              DW_AT_discr                    (reference to discriminant DW_TAG_member)
              DW_TAG_member                  (discriminant member)
              DW_TAG_variant                 (variant 1)
              DW_TAG_variant                 (variant 2)
              DW_TAG_variant                 (variant 3)
     --->   DW_TAG_structure_type            (type of variant 1)
     --->   DW_TAG_structure_type            (type of variant 2)
     --->   DW_TAG_structure_type            (type of variant 3)

In CPP-like mode, we have the exact same descriptions for each variant too:

          DW_TAG_union_type              (top-level type for enum)
            DW_TAG_member                    (member for variant 1)
            DW_TAG_member                    (member for variant 2)
            DW_TAG_member                    (member for variant 3)
     --->   DW_TAG_structure_type            (type of variant 1)
     --->   DW_TAG_structure_type            (type of variant 2)
     --->   DW_TAG_structure_type            (type of variant 3)
            DW_TAG_enumeration_type          (type of tag)

The node looks like:

    DW_TAG_structure_type
      DW_AT_name                  <name-of-variant>
      DW_AT_byte_size             0x00000010
      DW_AT_alignment             0x00000008
      DW_TAG_member
        DW_AT_name                  <name-of-field-0>
        DW_AT_type                  <0x0000018e>
        DW_AT_alignment             0x00000004
        DW_AT_data_member_location  4
      DW_TAG_member
        DW_AT_name                  <name-of-field-1>
        DW_AT_type                  <0x00000195>
        DW_AT_alignment             0x00000008
        DW_AT_data_member_location  8
      ...

The type of a variant is always a struct type with the name of the variant and a DW_TAG_member for each field (but not the discriminant).