[PATCH v4 11/19] gendwarfksyms: Add die_map debugging

Sami Tolvanen
2024-10-08T18:38:57Z

Debugging the DWARF processing can be somewhat challenging, so add
more detailed debugging output for die_map operations. Add the
--dump-die-map flag, which adds color coded tags to the output for
die_map changes.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Neal Gompa <neal@gompa.dev>
---
scripts/gendwarfksyms/dwarf.c | 15 +++++++++++++++
scripts/gendwarfksyms/gendwarfksyms.c | 7 +++++++
scripts/gendwarfksyms/gendwarfksyms.h | 13 +++++++++++++
3 files changed, 35 insertions(+)

diff --git a/scripts/gendwarfksyms/dwarf.c b/scripts/gendwarfksyms/dwarf.c
index 51dd8e82f9e7..d67cac16f8fb 100644
--- a/scripts/gendwarfksyms/dwarf.c
+++ b/scripts/gendwarfksyms/dwarf.c
@@ -103,6 +103,8 @@ static void process(struct die *cache, const char *s)
if (dump_dies)
fputs(s, stderr);

+ if (cache)
+ die_debug_r("cache %p string '%s'", cache, s);
die_map_add_string(cache, s);
}

@@ -552,6 +554,8 @@ static void process_cached(struct state *state, struct die *cache,
list_for_each_entry(df, &cache->fragments, list) {
switch (df->type) {
case FRAGMENT_STRING:
+ die_debug_b("cache %p STRING '%s'", cache,
+ df->data.str);
process(NULL, df->data.str);
break;
case FRAGMENT_LINEBREAK:
@@ -561,6 +565,8 @@ static void process_cached(struct state *state, struct die *cache,
if (!dwarf_die_addr_die(dwarf_cu_getdwarf(die->cu),
(void *)df->data.addr, &child))
error("dwarf_die_addr_die failed");
+ die_debug_b("cache %p DIE addr %" PRIxPTR " tag %x",
+ cache, df->data.addr, dwarf_tag(&child));
check(process_type(state, NULL, &child));
break;
default:
@@ -651,6 +657,9 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
cache = die_map_get(die, want_state);

if (cache->state == want_state) {
+ die_debug_g("cached addr %p tag %x -- %s", die->addr, tag,
+ die_state_name(cache->state));
+
if (want_state == DIE_COMPLETE && is_expanded_type(tag))
cache_mark_expanded(&state->expansion_cache, die->addr);

@@ -661,6 +670,9 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
return 0;
}

+ die_debug_g("addr %p tag %x -- %s -> %s", die->addr, tag,
+ die_state_name(cache->state), die_state_name(want_state));
+
switch (tag) {
/* Type modifiers */
PROCESS_TYPE(atomic)
@@ -696,6 +708,9 @@ static int process_type(struct state *state, struct die *parent, Dwarf_Die *die)
error("unexpected type: %x", tag);
}

+ die_debug_r("parent %p cache %p die addr %p tag %x", parent, cache,
+ die->addr, tag);
+
/* Update cache state and append to the parent (if any) */
cache->tag = tag;
cache->state = want_state;
diff --git a/scripts/gendwarfksyms/gendwarfksyms.c b/scripts/gendwarfksyms/gendwarfksyms.c
index 310cc9257d6e..d40692a703bb 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.c
+++ b/scripts/gendwarfksyms/gendwarfksyms.c
@@ -19,6 +19,8 @@
int debug;
/* Dump DIE contents */
int dump_dies;
+/* Print debugging information about die_map changes */
+int dump_die_map;

static void usage(void)
{
@@ -26,6 +28,7 @@ static void usage(void)
"Options:\n"
" -d, --debug Print debugging information\n"
" --dump-dies Dump DWARF DIE contents\n"
+ " --dump-die-map Print debugging information about die_map changes\n"
" -h, --help Print this message\n"
"\n",
stderr);
@@ -74,6 +77,7 @@ int main(int argc, char **argv)

struct option opts[] = { { "debug", 0, NULL, 'd' },
{ "dump-dies", 0, &dump_dies, 1 },
+ { "dump-die-map", 0, &dump_die_map, 1 },
{ "help", 0, NULL, 'h' },
{ 0, 0, NULL, 0 } };

@@ -93,6 +97,9 @@ int main(int argc, char **argv)
}
}

+ if (dump_die_map)
+ dump_dies = 1;
+
if (optind >= argc) {
usage();
error("no input files?");
diff --git a/scripts/gendwarfksyms/gendwarfksyms.h b/scripts/gendwarfksyms/gendwarfksyms.h
index 6147859ae2af..126916e85ee0 100644
--- a/scripts/gendwarfksyms/gendwarfksyms.h
+++ b/scripts/gendwarfksyms/gendwarfksyms.h
@@ -24,6 +24,7 @@
*/
extern int debug;
extern int dump_dies;
+extern int dump_die_map;

/*
* Output helpers
@@ -46,6 +47,18 @@ extern int dump_dies;
exit(1); \
} while (0)

+#define __die_debug(color, format, ...) \
+ do { \
+ if (dump_dies && dump_die_map) \
+ fprintf(stderr, \
+ "\033[" #color "m<" format ">\033[39m", \
+ __VA_ARGS__); \
+ } while (0)
+
+#define die_debug_r(format, ...) __die_debug(91, format, __VA_ARGS__)
+#define die_debug_g(format, ...) __die_debug(92, format, __VA_ARGS__)
+#define die_debug_b(format, ...) __die_debug(94, format, __VA_ARGS__)
+
/*
* Error handling helpers
*/