[PATCH 12/15] gendwarfksyms: Add inline debugging

Sami Tolvanen
2024-06-17T17:58:47Z

Understanding the operation and caching of the tool can be somewhat
challenging without a debugger. Add inline debugging information with
the --inline-debug command, which adds highlighted tags to the --debug
output with information about cache states etc.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
tools/gendwarfksyms/gendwarfksyms.c | 3 +++
tools/gendwarfksyms/gendwarfksyms.h | 29 +++++++++++++++++++++++++++++
tools/gendwarfksyms/types.c | 14 ++++++++++++++
3 files changed, 46 insertions(+)

diff --git a/tools/gendwarfksyms/gendwarfksyms.c b/tools/gendwarfksyms/gendwarfksyms.c
index 7095f0ecccab..acf4b44238e2 100644
--- a/tools/gendwarfksyms/gendwarfksyms.c
+++ b/tools/gendwarfksyms/gendwarfksyms.c
@@ -15,6 +15,8 @@

/* Print type descriptions and debugging output to stderr */
bool debug;
+/* Print inline debugging information to stderr (with --debug) */
+bool inline_debug;
/* Don't use caching */
bool no_cache;
/* Don't pretty-print (with --debug) */
@@ -25,6 +27,7 @@ static const struct {
bool *flag;
} options[] = {
{ "--debug", &debug },
+ { "--inline-debug", &inline_debug },
{ "--no-cache", &no_cache },
{ "--no-pretty-print", &no_pretty_print },
};
diff --git a/tools/gendwarfksyms/gendwarfksyms.h b/tools/gendwarfksyms/gendwarfksyms.h
index 568f3727017e..34d1be3cfb7f 100644
--- a/tools/gendwarfksyms/gendwarfksyms.h
+++ b/tools/gendwarfksyms/gendwarfksyms.h
@@ -18,6 +18,7 @@
* Options -- in gendwarfksyms.c
*/
extern bool debug;
+extern bool inline_debug;
extern bool no_cache;
extern bool no_pretty_print;

@@ -38,6 +39,18 @@ extern bool no_pretty_print;
#define warn(format, ...) __println("warning: ", format, ##__VA_ARGS__)
#define error(format, ...) __println("error: ", format, ##__VA_ARGS__)

+#define __inline_debug(color, format, ...) \
+ do { \
+ if (debug && inline_debug) \
+ fprintf(stderr, \
+ "\033[" #color "m<" format ">\033[39m", \
+ __VA_ARGS__); \
+ } while (0)
+
+#define inline_debug_r(format, ...) __inline_debug(91, format, __VA_ARGS__)
+#define inline_debug_g(format, ...) __inline_debug(92, format, __VA_ARGS__)
+#define inline_debug_b(format, ...) __inline_debug(94, format, __VA_ARGS__)
+
/*
* Error handling helpers
*/
@@ -51,6 +64,9 @@ extern bool no_pretty_print;
__res; \
})

+/*
+ * DWARF helpers
+ */
/* 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
@@ -97,6 +113,19 @@ struct cached_item {

enum cached_die_state { INCOMPLETE, UNEXPANDED, COMPLETE };

+static inline const char *cache_state_name(enum cached_die_state state)
+{
+ switch (state) {
+ default:
+ case INCOMPLETE:
+ return "INCOMPLETE";
+ case UNEXPANDED:
+ return "UNEXPANDED";
+ case COMPLETE:
+ return "COMPLETE";
+ }
+}
+
struct cached_die {
enum cached_die_state state;
uintptr_t addr;
diff --git a/tools/gendwarfksyms/types.c b/tools/gendwarfksyms/types.c
index da3aa2ad9f57..694b33cdd606 100644
--- a/tools/gendwarfksyms/types.c
+++ b/tools/gendwarfksyms/types.c
@@ -97,6 +97,7 @@ static int process(struct state *state, struct cached_die *cache, const char *s)
fputs(s, stderr);

state->crc = partial_crc32(s, state->crc);
+ inline_debug_r("cache %p string '%s'", cache, s);
return cache_add_string(cache, s);
}

@@ -456,6 +457,8 @@ static int process_cached(struct state *state, struct cached_die *cache,
while (ci) {
switch (ci->type) {
case STRING:
+ inline_debug_b("cache %p STRING '%s'", cache,
+ ci->data.str);
check(process(state, NULL, ci->data.str));
break;
case LINEBREAK:
@@ -468,6 +471,8 @@ static int process_cached(struct state *state, struct cached_die *cache,
error("dwarf_die_addr_die failed");
return -1;
}
+ inline_debug_b("cache %p DIE addr %lx tag %d", cache,
+ ci->data.addr, dwarf_tag(&child));
check(process_type(state, NULL, &child));
break;
default:
@@ -561,6 +566,9 @@ static int process_type(struct state *state, struct cached_die *parent,
check(cache_get(die, want_state, &cache));

if (cache->state == want_state) {
+ inline_debug_g("cached addr %p tag %d -- %s", die->addr,
+ tag, cache_state_name(cache->state));
+
if (want_state == COMPLETE && is_expanded_type(tag))
check(cache_mark_expanded(die));

@@ -572,6 +580,9 @@ static int process_type(struct state *state, struct cached_die *parent,
}
}

+ inline_debug_g("addr %p tag %d -- INCOMPLETE -> %s", die->addr, tag,
+ cache_state_name(want_state));
+
switch (tag) {
/* Type modifiers */
PROCESS_TYPE(atomic)
@@ -608,6 +619,9 @@ static int process_type(struct state *state, struct cached_die *parent,
}

if (!no_cache) {
+ inline_debug_r("parent %p cache %p die addr %p tag %d", parent,
+ cache, die->addr, tag);
+
/* Update cache state and append to the parent (if any) */
cache->state = want_state;
check(cache_add_die(parent, die));
--
2.45.2.627.g7a2c4fd464-goog