[evolution-data-server] camel-debug: Cache symbol resolution to speed up backtrace demangle

[Milan Crha <mcrha src gnome org>]

commit 9dcf3b41b84b57a816975350d6020f632d777453
Author: Milan Crha <mcrha redhat com>
Date:   Wed Jan 20 09:58:35 2021 +0100

    camel-debug: Cache symbol resolution to speed up backtrace demangle

 src/camel/camel-debug.c | 60 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 9 deletions(-)
---
diff --git a/src/camel/camel-debug.c b/src/camel/camel-debug.c
index 10be94602..ce12a4466 100644
--- a/src/camel/camel-debug.c
+++ b/src/camel/camel-debug.c
@@ -487,15 +487,14 @@ getmodules_callback (Dwfl_Module *module,
 #endif /* HAVE_ELFUTILS_LIBDWFL */
 
 static const gchar *
-addr_lookup (gpointer addr,
-             const gchar **file_path,
-             gint *lineno,
-             const gchar *fallback)
+addr_lookup_dwfl (gpointer addr,
+                 const gchar **file_path,
+                 gint *lineno,
+                 const gchar *fallback)
 {
 #ifdef HAVE_ELFUTILS_LIBDWFL
        Dwfl *dwfl = dwfl_get (FALSE);
        struct getmodules_callback_arg arg;
-       static GMutex mutex;
 
        if (!dwfl)
                return NULL;
@@ -505,8 +504,6 @@ addr_lookup (gpointer addr,
        arg.file_path = NULL;
        arg.lineno = -1;
 
-       g_mutex_lock (&mutex);
-
        dwfl_getmodules (dwfl, getmodules_callback, &arg, 0);
 
        if (!arg.func_name && fallback && strstr (fallback, "/lib") != fallback && strstr (fallback, 
"/usr/lib") != fallback) {
@@ -515,8 +512,6 @@ addr_lookup (gpointer addr,
                        dwfl_getmodules (dwfl, getmodules_callback, &arg, 0);
        }
 
-       g_mutex_unlock (&mutex);
-
        *file_path = arg.file_path;
        *lineno = arg.lineno;
 
@@ -526,6 +521,53 @@ addr_lookup (gpointer addr,
 #endif /* HAVE_ELFUTILS_LIBDWFL */
 }
 
+typedef struct _SymbolData {
+       const gchar *func_name;
+       const gchar *file_path;
+       gint lineno;
+} SymbolData;
+
+static const gchar *
+addr_lookup (gpointer addr,
+             const gchar **file_path,
+             gint *lineno,
+             const gchar *fallback)
+{
+       static GHashTable *symbols_cache = NULL;
+       static GMutex mutex;
+       SymbolData *sd, sd_local;
+
+       g_mutex_lock (&mutex);
+       if (symbols_cache) {
+               sd = g_hash_table_lookup (symbols_cache, addr);
+               if (sd) {
+                       g_mutex_unlock (&mutex);
+                       *file_path = sd->file_path;
+                       *lineno = sd->lineno;
+
+                       return sd->func_name;
+               }
+       }
+
+       sd_local.func_name = addr_lookup_dwfl (addr, &sd_local.file_path, &sd_local.lineno, fallback);
+       if (sd_local.func_name) {
+               if (!symbols_cache)
+                       symbols_cache = g_hash_table_new_full (NULL, NULL, NULL, g_free);
+               sd = g_new (SymbolData, 1);
+               sd->func_name = sd_local.func_name;
+               sd->file_path = sd_local.file_path;
+               sd->lineno = sd_local.lineno;
+               g_hash_table_insert (symbols_cache, addr, sd);
+       }
+
+       g_mutex_unlock (&mutex);
+
+       *file_path = sd_local.file_path;
+       *lineno = sd_local.lineno;
+
+       return sd_local.func_name;
+}
+
 #endif /* HAVE_BACKTRACE_SYMBOLS */
 
 static void