[PATCH v4 07/19] gendwarfksyms: Expand subroutine_type

Sami Tolvanen
2024-10-08T18:38:50Z

Add support for expanding DW_TAG_subroutine_type and the parameters
in DW_TAG_formal_parameter. Use this to also expand subprograms.

Example output with --dump-dies:

subprogram (
formal_parameter pointer_type {
const_type {
base_type char byte_size(1) encoding(6)
}
}
)
-> base_type unsigned long byte_size(8) encoding(7)

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/dwarf.c | 84 ++++++++++++++++++++++++++-
scripts/gendwarfksyms/gendwarfksyms.h | 4 ++
2 files changed, 85 insertions(+), 3 deletions(-)

diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index 1d67ee18a388..7e6b477d7c12 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -211,6 +211,15 @@ DEFINE_PROCESS_UDATA_ATTRIBUTE(alignment)
DEFINE_PROCESS_UDATA_ATTRIBUTE(byte_size)
DEFINE_PROCESS_UDATA_ATTRIBUTE(encoding)

+/* Match functions -- die_match_callback_t */
+#define DEFINE_MATCH(type) \
+ static bool match_##type##_type(Dwarf_Die *die) \
+ { \
+ return dwarf_tag(die) == DW_TAG_##type##_type; \
+ }
+
+DEFINE_MATCH(formal_parameter)
+
bool match_all(Dwarf_Die *die)
{
return true;
@@ -223,19 +232,28 @@ int process_die_container(struct state *state, struct die *cache,
Dwarf_Die current;
int res;

+ /* Track the first item in lists. */
+ if (state)
+ state->first_list_item = true;
+
res = checkp(dwarf_child(die, &current));
while (!res) {
if (match(&current)) {
/* <0 = error, 0 = continue, >0 = stop */
res = checkp(func(state, cache, &current));
if (res)
- return res;
+ goto out;
}

res = checkp(dwarf_siblingof(&current, &current));
}

- return 0;
+ res = 0;
+out:
+ if (state)
+ state->first_list_item = false;
+
+ return res;
}

static int process_type(struct state *state, struct die *parent,
@@ -255,6 +273,40 @@ static void process_type_attr(struct state *state, struct die *cache,
process(cache, "base_type void");
}

+static void process_list_comma(struct state *state, struct die *cache)
+{
+ if (state->first_list_item) {
+ state->first_list_item = false;
+ } else {
+ process(cache, " ,");
+ process_linebreak(cache, 0);
+ }
+}
+
+/* Comma-separated with DW_AT_type */
+static void __process_list_type(struct state *state, struct die *cache,
+ Dwarf_Die *die, const char *type)
+{
+ const char *name = get_name_attr(die);
+
+ process_list_comma(state, cache);
+ process(cache, type);
+ process_type_attr(state, cache, die);
+ if (name) {
+ process(cache, " ");
+ process(cache, name);
+ }
+}
+
+#define DEFINE_PROCESS_LIST_TYPE(type) \
+ static void process_##type##_type(struct state *state, \
+ struct die *cache, Dwarf_Die *die) \
+ { \
+ __process_list_type(state, cache, die, #type " "); \
+ }
+
+DEFINE_PROCESS_LIST_TYPE(formal_parameter)
+
/* Container types with DW_AT_type */
static void __process_type(struct state *state, struct die *cache,
Dwarf_Die *die, const char *type)
@@ -289,6 +341,29 @@ DEFINE_PROCESS_TYPE(shared)
DEFINE_PROCESS_TYPE(volatile)
DEFINE_PROCESS_TYPE(typedef)

+static void __process_subroutine_type(struct state *state, struct die *cache,
+ Dwarf_Die *die, const char *type)
+{
+ process(cache, type);
+ process(cache, " (");
+ process_linebreak(cache, 1);
+ /* Parameters */
+ check(process_die_container(state, cache, die, process_type,
+ match_formal_parameter_type));
+ process_linebreak(cache, -1);
+ process(cache, ")");
+ process_linebreak(cache, 0);
+ /* Return type */
+ process(cache, "-> ");
+ process_type_attr(state, cache, die);
+}
+
+static void process_subroutine_type(struct state *state, struct die *cache,
+ Dwarf_Die *die)
+{
+ __process_subroutine_type(state, cache, die, "subroutine_type");
+}
+
static void process_base_type(struct state *state, struct die *cache,
Dwarf_Die *die)
{
@@ -359,8 +434,11 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
PROCESS_TYPE(rvalue_reference)
PROCESS_TYPE(shared)
PROCESS_TYPE(volatile)
+ /* Subtypes */
+ PROCESS_TYPE(formal_parameter)
/* Other types */
PROCESS_TYPE(base)
+ PROCESS_TYPE(subroutine)
PROCESS_TYPE(typedef)
default:
debug("unimplemented type: %x", tag);
@@ -390,7 +468,7 @@ static void process_symbol(struct state *state, Dwarf_Die *die,
static int __process_subprogram(struct state *state, struct die *cache,
Dwarf_Die *die)
{
- process(cache, "subprogram");
+ __process_subroutine_type(state, cache, die, "subprogram");
return 0;
}

diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
index f2be353c3b0b..f31bfcb0dfe7 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -63,6 +63,7 @@ extern int dump_dies;
#define checkp(expr) __check(expr, __res < 0)

/* Consistent aliases (DW_TAG_<type>_type) for DWARF tags */
+#define DW_TAG_formal_parameter_type DW_TAG_formal_parameter
#define DW_TAG_typedef_type DW_TAG_typedef

/*
@@ -156,6 +157,9 @@ void die_map_free(void);
struct state {
struct symbol *sym;
Dwarf_Die die;
+
+ /* List expansion */
+ bool first_list_item;
};

typedef int (*die_callback_t)(struct state *state, struct die *cache,