[PATCH 12/15] gendwarfksyms: Add inline debugging

[Sami Tolvanen <samitolvanen@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 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