gendwarfksyms: Add die_map debugging

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>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Author: samitolvanen

scripts/gendwarfksyms/dwarf.c

@@ -146,6 +146,8 @@ 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);
 }
 
@@ -594,6 +596,8 @@ 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:
@@ -603,6 +607,8 @@ 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:
@@ -671,13 +677,19 @@ 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));
+
 		process_cached(state, cache, die);
 		die_map_add_die(parent, cache);
 
 		expansion_state_restore(&state->expand, &saved);
 		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)
@@ -713,6 +725,9 @@ 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;

scripts/gendwarfksyms/gendwarfksyms.c

@@ -19,13 +19,16 @@
 int debug;
 /* Dump DIE contents */
 int dump_dies;
+/* Print debugging information about die_map changes */
+int dump_die_map;
 
 static void usage(void)
 {
 	fputs("Usage: gendwarfksyms [options] elf-object-file ... < symbol-list\n\n"
 	      "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);
@@ -75,6 +78,7 @@ int main(int argc, char **argv)
 	static const 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 }
 	};
@@ -95,6 +99,9 @@ int main(int argc, char **argv)
 		}
 	}
 
+	if (dump_die_map)
+		dump_dies = 1;
+
 	if (optind >= argc) {
 		usage();
 		error("no input files?");

scripts/gendwarfksyms/gendwarfksyms.h

@@ -21,6 +21,7 @@
  */
 extern int debug;
 extern int dump_dies;
+extern int dump_die_map;
 
 /*
  * Output helpers
@@ -43,6 +44,18 @@ 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
  */