Add support for expanding DWARF type modifiers, such as pointers,
const values etc., and typedefs. These types all have DW_AT_type
attribute pointing to the underlying type, and thus produce similar
output.

Also add linebreaks and indentation to debugging output to make it
more readable.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
---
 scripts/gendwarfksyms/die.c           | 12 +++++
 scripts/gendwarfksyms/dwarf.c         | 67 +++++++++++++++++++++++++++
 scripts/gendwarfksyms/gendwarfksyms.h |  5 ++
 3 files changed, 84 insertions(+)

diff --git a/scripts/gendwarfksyms/die.c b/scripts/gendwarfksyms/die.c
index 28d89fce89fc..2829387fd815 100644
--- a/scripts/gendwarfksyms/die.c
+++ b/scripts/gendwarfksyms/die.c
@@ -130,6 +130,18 @@ void die_map_add_string(struct die *cd, const char *str)
 	df->type = FRAGMENT_STRING;
 }
 
+void die_map_add_linebreak(struct die *cd, int linebreak)
+{
+	struct die_fragment *df;
+
+	if (!cd)
+		return;
+
+	df = append_item(cd);
+	df->data.linebreak = linebreak;
+	df->type = FRAGMENT_LINEBREAK;
+}
+
 void die_map_add_die(struct die *cd, struct die *child)
 {
 	struct die_fragment *df;
diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index c2cd4743515e..1d67ee18a388 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -6,6 +6,17 @@
 #include <stdarg.h>
 #include "gendwarfksyms.h"
 
+static bool do_linebreak;
+static int indentation_level;
+
+/* Line breaks and indentation for pretty-printing */
+static void process_linebreak(struct die *cache, int n)
+{
+	indentation_level += n;
+	do_linebreak = true;
+	die_map_add_linebreak(cache, n);
+}
+
 #define DEFINE_GET_ATTR(attr, type)                                    \
 	static bool get_##attr##_attr(Dwarf_Die *die, unsigned int id, \
 				      type *value)                     \
@@ -75,6 +86,12 @@ static void process(struct die *cache, const char *s)
 {
 	s = s ?: "<null>";
 
+	if (dump_dies && do_linebreak) {
+		fputs("\n", stderr);
+		for (int i = 0; i < indentation_level; i++)
+			fputs("  ", stderr);
+		do_linebreak = false;
+	}
 	if (dump_dies)
 		fputs(s, stderr);
 
@@ -238,6 +255,40 @@ static void process_type_attr(struct state *state, struct die *cache,
 	process(cache, "base_type void");
 }
 
+/* Container types with DW_AT_type */
+static void __process_type(struct state *state, struct die *cache,
+			   Dwarf_Die *die, const char *type)
+{
+	process(cache, type);
+	process_fqn(cache, die);
+	process(cache, " {");
+	process_linebreak(cache, 1);
+	process_type_attr(state, cache, die);
+	process_linebreak(cache, -1);
+	process(cache, "}");
+	process_byte_size_attr(cache, die);
+	process_alignment_attr(cache, die);
+}
+
+#define DEFINE_PROCESS_TYPE(type)                                            \
+	static void process_##type##_type(struct state *state,               \
+					  struct die *cache, Dwarf_Die *die) \
+	{                                                                    \
+		__process_type(state, cache, die, #type "_type");            \
+	}
+
+DEFINE_PROCESS_TYPE(atomic)
+DEFINE_PROCESS_TYPE(const)
+DEFINE_PROCESS_TYPE(immutable)
+DEFINE_PROCESS_TYPE(packed)
+DEFINE_PROCESS_TYPE(pointer)
+DEFINE_PROCESS_TYPE(reference)
+DEFINE_PROCESS_TYPE(restrict)
+DEFINE_PROCESS_TYPE(rvalue_reference)
+DEFINE_PROCESS_TYPE(shared)
+DEFINE_PROCESS_TYPE(volatile)
+DEFINE_PROCESS_TYPE(typedef)
+
 static void process_base_type(struct state *state, struct die *cache,
 			      Dwarf_Die *die)
 {
@@ -259,6 +310,9 @@ static void process_cached(struct state *state, struct die *cache,
 		case FRAGMENT_STRING:
 			process(NULL, df->data.str);
 			break;
+		case FRAGMENT_LINEBREAK:
+			process_linebreak(NULL, df->data.linebreak);
+			break;
 		case FRAGMENT_DIE:
 			if (!dwarf_die_addr_die(dwarf_cu_getdwarf(die->cu),
 						(void *)df->data.addr, &child))
@@ -294,7 +348,20 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
 	}
 
 	switch (tag) {
+	/* Type modifiers */
+	PROCESS_TYPE(atomic)
+	PROCESS_TYPE(const)
+	PROCESS_TYPE(immutable)
+	PROCESS_TYPE(packed)
+	PROCESS_TYPE(pointer)
+	PROCESS_TYPE(reference)
+	PROCESS_TYPE(restrict)
+	PROCESS_TYPE(rvalue_reference)
+	PROCESS_TYPE(shared)
+	PROCESS_TYPE(volatile)
+	/* Other types */
 	PROCESS_TYPE(base)
+	PROCESS_TYPE(typedef)
 	default:
 		debug("unimplemented type: %x", tag);
 		break;
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
index b2aded992d42..206ba8e3f1a8 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -62,6 +62,9 @@ extern int dump_dies;
 /* Error == negative values */
 #define checkp(expr) __check(expr, __res < 0)
 
+/* Consistent aliases (DW_TAG_<type>_type) for DWARF tags */
+#define DW_TAG_typedef_type DW_TAG_typedef
+
 /*
  * symbols.c
  */
@@ -103,6 +106,7 @@ enum die_state {
 enum die_fragment_type {
 	FRAGMENT_EMPTY,
 	FRAGMENT_STRING,
+	FRAGMENT_LINEBREAK,
 	FRAGMENT_DIE
 };
 
@@ -110,6 +114,7 @@ struct die_fragment {
 	enum die_fragment_type type;
 	union {
 		char *str;
+		int linebreak;
 		uintptr_t addr;
 	} data;
 	struct list_head list;
-- 
2.47.0.163.g1226f6d8fa-goog