[PATCH v4 09/19] gendwarfksyms: Expand structure types

[Sami Tolvanen <samitolvanen@google.com>]

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@google.com>
Acked-by: Neal Gompa <neal@gompa.dev>
---
 scripts/gendwarfksyms/dwarf.c         | 138 +++++++++++++++++++++++++-
 scripts/gendwarfksyms/gendwarfksyms.h |   5 +
 2 files changed, 141 insertions(+), 2 deletions(-)

diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index ade9b3b7b119..f5cebbdcc212 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -207,9 +207,14 @@ 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)
+DEFINE_PROCESS_UDATA_ATTRIBUTE(discr_value)
 
 /* Match functions -- die_match_callback_t */
 #define DEFINE_MATCH(type)                                     \
@@ -218,7 +223,9 @@ 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)
 
 bool match_all(Dwarf_Die *die)
@@ -297,6 +304,10 @@ 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)                                       \
@@ -307,6 +318,7 @@ 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,
@@ -339,6 +351,7 @@ 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)
 
@@ -392,6 +405,107 @@ 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, "}");
+	process_discr_value_attr(cache, die);
+}
+
+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_all));
+	process_linebreak(cache, -1);
+	process(cache, "}");
+}
+
+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)
 {
@@ -402,6 +516,16 @@ 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.
+	 */
+	process(cache, "unspecified_type");
+}
+
 static void process_cached(struct state *state, struct die *cache,
 			   Dwarf_Die *die)
 {
@@ -462,17 +586,27 @@ 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 f31bfcb0dfe7..f317de5b0653 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
-- 
2.47.0.rc0.187.ge670bccf7e-goog