Re: [PATCH v3 10/20] gendwarfksyms: Expand structure types
From: Petr Pavlu
Date: Tue Oct 01 2024 - 10:20:32 EST
On 9/23/24 20:18, Sami Tolvanen wrote:
> Recursively expand DWARF structure types, i.e. structs, unions, and
> enums. Also include relevant DWARF attributes in type strings to
> encode structure layout, for example.
>
> Example output with --dump-dies:
>
> subprogram (
> formal_parameter structure_type &str {
> member pointer_type {
> base_type u8 byte_size(1) encoding(7)
> } data_ptr data_member_location(0) ,
> member base_type usize byte_size(8) encoding(7) length data_member_location(8)
> } byte_size(16) alignment(8) msg
> )
> -> base_type void
>
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> ---
> scripts/gendwarfksyms/dwarf.c | 137 +++++++++++++++++++++++++-
> scripts/gendwarfksyms/gendwarfksyms.h | 5 +
> 2 files changed, 140 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
> index caf25da0a9b9..b7f1dc29cb9c 100644
> --- a/scripts/gendwarfksyms/dwarf.c
> +++ b/scripts/gendwarfksyms/dwarf.c
> @@ -205,9 +205,13 @@ static void process_fqn(struct die *cache, Dwarf_Die *die)
> value); \
> }
>
> +DEFINE_PROCESS_UDATA_ATTRIBUTE(accessibility)
> DEFINE_PROCESS_UDATA_ATTRIBUTE(alignment)
> +DEFINE_PROCESS_UDATA_ATTRIBUTE(bit_size)
> DEFINE_PROCESS_UDATA_ATTRIBUTE(byte_size)
> DEFINE_PROCESS_UDATA_ATTRIBUTE(encoding)
> +DEFINE_PROCESS_UDATA_ATTRIBUTE(data_bit_offset)
> +DEFINE_PROCESS_UDATA_ATTRIBUTE(data_member_location)
>
> /* Match functions -- die_match_callback_t */
> #define DEFINE_MATCH(type) \
> @@ -216,8 +220,11 @@ DEFINE_PROCESS_UDATA_ATTRIBUTE(encoding)
> return dwarf_tag(die) == DW_TAG_##type##_type; \
> }
>
> +DEFINE_MATCH(enumerator)
> DEFINE_MATCH(formal_parameter)
> +DEFINE_MATCH(member)
> DEFINE_MATCH(subrange)
> +DEFINE_MATCH(variant)
>
> bool match_all(Dwarf_Die *die)
> {
> @@ -295,6 +302,10 @@ static void __process_list_type(struct state *state, struct die *cache,
> process(cache, " ");
> process(cache, name);
> }
> + process_accessibility_attr(cache, die);
> + process_bit_size_attr(cache, die);
> + process_data_bit_offset_attr(cache, die);
> + process_data_member_location_attr(cache, die);
> }
>
> #define DEFINE_PROCESS_LIST_TYPE(type) \
> @@ -305,6 +316,7 @@ static void __process_list_type(struct state *state, struct die *cache,
> }
>
> DEFINE_PROCESS_LIST_TYPE(formal_parameter)
> +DEFINE_PROCESS_LIST_TYPE(member)
>
> /* Container types with DW_AT_type */
> static void __process_type(struct state *state, struct die *cache,
> @@ -337,6 +349,7 @@ DEFINE_PROCESS_TYPE(reference)
> DEFINE_PROCESS_TYPE(restrict)
> DEFINE_PROCESS_TYPE(rvalue_reference)
> DEFINE_PROCESS_TYPE(shared)
> +DEFINE_PROCESS_TYPE(template_type_parameter)
> DEFINE_PROCESS_TYPE(volatile)
> DEFINE_PROCESS_TYPE(typedef)
>
> @@ -390,6 +403,106 @@ static void process_subroutine_type(struct state *state, struct die *cache,
> __process_subroutine_type(state, cache, die, "subroutine_type");
> }
>
> +static void process_variant_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + process_list_comma(state, cache);
> + process(cache, "variant {");
> + process_linebreak(cache, 1);
> + check(process_die_container(state, cache, die, process_type,
> + match_member_type));
> + process_linebreak(cache, -1);
> + process(cache, "}");
> +}
> +
> +static void process_variant_part_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + process_list_comma(state, cache);
> + process(cache, "variant_part {");
> + process_linebreak(cache, 1);
> + check(process_die_container(state, cache, die, process_type,
> + match_variant_type));
> + process_linebreak(cache, -1);
> + process(cache, "}");
> +}
For variant types, should the tool worry also about DW_AT_discr and
DW_AT_discr_value?
> +
> +static int ___process_structure_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + switch (dwarf_tag(die)) {
> + case DW_TAG_member:
> + case DW_TAG_variant_part:
> + return check(process_type(state, cache, die));
> + case DW_TAG_class_type:
> + case DW_TAG_enumeration_type:
> + case DW_TAG_structure_type:
> + case DW_TAG_template_type_parameter:
> + case DW_TAG_union_type:
> + case DW_TAG_subprogram:
> + /* Skip non-member types, including member functions */
> + return 0;
> + default:
> + error("unexpected structure_type child: %x", dwarf_tag(die));
> + }
> +}
> +
> +static void __process_structure_type(struct state *state, struct die *cache,
> + Dwarf_Die *die, const char *type,
> + die_callback_t process_func,
> + die_match_callback_t match_func)
> +{
> + process(cache, type);
> + process_fqn(cache, die);
> + process(cache, " {");
> + process_linebreak(cache, 1);
> +
> + check(process_die_container(state, cache, die, process_func,
> + match_func));
> +
> + process_linebreak(cache, -1);
> + process(cache, "}");
> +
> + process_byte_size_attr(cache, die);
> + process_alignment_attr(cache, die);
> +}
> +
> +#define DEFINE_PROCESS_STRUCTURE_TYPE(structure) \
> + static void process_##structure##_type( \
> + struct state *state, struct die *cache, Dwarf_Die *die) \
> + { \
> + __process_structure_type(state, cache, die, \
> + #structure "_type", \
> + ___process_structure_type, \
> + match_all); \
> + }
> +
> +DEFINE_PROCESS_STRUCTURE_TYPE(class)
> +DEFINE_PROCESS_STRUCTURE_TYPE(structure)
> +DEFINE_PROCESS_STRUCTURE_TYPE(union)
> +
> +static void process_enumerator_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + Dwarf_Word value;
> +
> + process_list_comma(state, cache);
> + process(cache, "enumerator");
> + process_fqn(cache, die);
> +
> + if (get_udata_attr(die, DW_AT_const_value, &value)) {
> + process(cache, " = ");
> + process_fmt(cache, "%" PRIu64, value);
> + }
> +}
> +
> +static void process_enumeration_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + __process_structure_type(state, cache, die, "enumeration_type",
> + process_type, match_enumerator_type);
> +}
> +
> static void process_base_type(struct state *state, struct die *cache,
> Dwarf_Die *die)
> {
> @@ -400,6 +513,16 @@ static void process_base_type(struct state *state, struct die *cache,
> process_alignment_attr(cache, die);
> }
>
> +static void process_unspecified_type(struct state *state, struct die *cache,
> + Dwarf_Die *die)
> +{
> + /*
> + * These can be emitted for stand-elone assembly code, which means we
> + * might run into them in vmlinux.o.
> + */
Nit: stand-elone -> stand-alone.
> + process(cache, "unspecified_type");
> +}
> +
> static void process_cached(struct state *state, struct die *cache,
> Dwarf_Die *die)
> {
> @@ -460,17 +583,27 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
> PROCESS_TYPE(rvalue_reference)
> PROCESS_TYPE(shared)
> PROCESS_TYPE(volatile)
> + /* Container types */
> + PROCESS_TYPE(class)
> + PROCESS_TYPE(structure)
> + PROCESS_TYPE(union)
> + PROCESS_TYPE(enumeration)
> /* Subtypes */
> + PROCESS_TYPE(enumerator)
> PROCESS_TYPE(formal_parameter)
> + PROCESS_TYPE(member)
> PROCESS_TYPE(subrange)
> + PROCESS_TYPE(template_type_parameter)
> + PROCESS_TYPE(variant)
> + PROCESS_TYPE(variant_part)
> /* Other types */
> PROCESS_TYPE(array)
> PROCESS_TYPE(base)
> PROCESS_TYPE(subroutine)
> PROCESS_TYPE(typedef)
> + PROCESS_TYPE(unspecified)
> default:
> - debug("unimplemented type: %x", tag);
> - break;
> + error("unexpected type: %x", tag);
> }
>
> /* Update cache state and append to the parent (if any) */
> diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
> index d5186472f705..ad50e35e3351 100644
> --- a/scripts/gendwarfksyms/gendwarfksyms.h
> +++ b/scripts/gendwarfksyms/gendwarfksyms.h
> @@ -63,8 +63,13 @@ extern int dump_dies;
> #define checkp(expr) __check(expr, __res < 0)
>
> /* Consistent aliases (DW_TAG_<type>_type) for DWARF tags */
> +#define DW_TAG_enumerator_type DW_TAG_enumerator
> #define DW_TAG_formal_parameter_type DW_TAG_formal_parameter
> +#define DW_TAG_member_type DW_TAG_member
> +#define DW_TAG_template_type_parameter_type DW_TAG_template_type_parameter
> #define DW_TAG_typedef_type DW_TAG_typedef
> +#define DW_TAG_variant_part_type DW_TAG_variant_part
> +#define DW_TAG_variant_type DW_TAG_variant
>
> /*
> * symbols.c
--
Thanks,
Petr