auxiliary: add reference count debugging code

2 files changed, 185 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_debug_refcnt.c b/src/gallium/auxiliary/util/u_debug_refcnt.c
new file mode 100644
index 00000000000..9d6fca56ab3
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_debug_refcnt.c
@@ -0,0 +1,156 @@
+#if defined(DEBUG) && (!defined(PIPE_OS_WINDOWS) || defined(PIPE_SUBSYSTEM_WINDOWS_USER))
+
+/* see http://www.mozilla.org/performance/refcnt-balancer.html for what do with the output
+ * on Linux, use tools/addr2line.sh to postprocess it before anything else
+ **/
+#include <util/u_debug.h>
+#include <util/u_debug_refcnt.h>
+#include <util/u_debug_stack.h>
+#include <util/u_debug_symbol.h>
+#include <util/u_string.h>
+#include <util/u_hash_table.h>
+#include <os/os_thread.h>
+#include <os/os_stream.h>
+
+int debug_refcnt_state;
+
+struct os_stream* stream;
+
+/* TODO: maybe move this serial machinery to a stand-alone module and expose it? */
+static pipe_mutex serials_mutex;
+static struct util_hash_table* serials_hash;
+static unsigned serials_last;
+
+static unsigned hash_ptr(void* p)
+{
+   return (unsigned)(uintptr_t)p;
+}
+
+static int compare_ptr(void* a, void* b)
+{
+   if(a == b)
+      return 0;
+   else if(a < b)
+      return -1;
+   else
+      return 1;
+}
+
+static boolean debug_serial(void* p, unsigned* pserial)
+{
+   unsigned serial;
+   boolean found = TRUE;
+   pipe_mutex_lock(serials_mutex);
+   if(!serials_hash)
+      serials_hash = util_hash_table_create(hash_ptr, compare_ptr);
+   serial = (unsigned)(uintptr_t)util_hash_table_get(serials_hash, p);
+   if(!serial)
+   {
+      /* time to stop logging... (you'll have a 100 GB logfile at least at this point)
+       * TODO: avoid this
+       */
+      serial = ++serials_last;
+      if(!serial)
+      {
+         debug_error("More than 2^32 objects detected, aborting.\n");
+         os_abort();
+      }
+
+      util_hash_table_set(serials_hash, p, (void*)(uintptr_t)serial);
+      found = FALSE;
+   }
+   pipe_mutex_unlock(serials_mutex);
+   *pserial = serial;
+   return found;
+}
+
+static void debug_serial_delete(void* p)
+{
+   pipe_mutex_lock(serials_mutex);
+   util_hash_table_remove(serials_hash, p);
+   pipe_mutex_unlock(serials_mutex);
+}
+
+#define STACK_LEN 64
+
+static void dump_stack(const char* symbols[STACK_LEN])
+{
+   unsigned i;
+   for(i = 0; i < STACK_LEN; ++i)
+   {
+      if(symbols[i])
+         os_stream_printf(stream, "%s\n", symbols[i]);
+   }
+   os_stream_write(stream, "\n", 1);
+}
+
+void debug_reference_slowpath(const struct pipe_reference* p, void* pget_desc, int change)
+{
+   if(debug_refcnt_state < 0)
+      return;
+
+   if(!debug_refcnt_state)
+   {
+      const char* filename = debug_get_option("GALLIUM_REFCNT_LOG", NULL);
+      if(filename && filename[0])
+         stream = os_file_stream_create(filename);
+
+      if(stream)
+         debug_refcnt_state = 1;
+      else
+         debug_refcnt_state = -1;
+   }
+
+   if(debug_refcnt_state > 0)
+   {
+      struct debug_stack_frame frames[STACK_LEN];
+      const char* symbols[STACK_LEN];
+      char buf[1024];
+
+      void (*get_desc)(char*, const struct pipe_reference*) = pget_desc;
+      unsigned i;
+      unsigned refcnt = p->count;
+      unsigned serial;
+      boolean existing = debug_serial((void*)p, &serial);
+
+      debug_backtrace_capture(frames, 1, STACK_LEN);
+      for(i = 0; i < STACK_LEN; ++i)
+      {
+         if(frames[i].function)
+            symbols[i] = debug_symbol_name_cached(frames[i].function);
+         else
+            symbols[i] = 0;
+      }
+
+      get_desc(buf, p);
+
+      if(!existing)
+      {
+         os_stream_printf(stream, "<%s> %p %u Create\n", buf, p, serial);
+         dump_stack(symbols);
+
+         /* this is there to provide a gradual change even if we don't see the initialization */
+         for(i = 1; i <= refcnt - change; ++i)
+         {
+            os_stream_printf(stream, "<%s> %p %u AddRef %u\n", buf, p, serial, i);
+            dump_stack(symbols);
+         }
+      }
+
+      if(change)
+      {
+         os_stream_printf(stream, "<%s> %p %u %s %u\n", buf, p, serial, change > 0 ? "AddRef" : "Release", refcnt);
+         dump_stack(symbols);
+      }
+
+      if(!refcnt)
+      {
+         debug_serial_delete((void*)p);
+         os_stream_printf(stream, "<%s> %p %u Destroy\n", buf, p, serial);
+         dump_stack(symbols);
+      }
+
+      os_stream_flush(stream);
+   }
+}
+#endif
diff --git a/src/gallium/auxiliary/util/u_debug_refcnt.h b/src/gallium/auxiliary/util/u_debug_refcnt.h
new file mode 100644
index 00000000000..e48a2a645cc
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_debug_refcnt.h
@@ -0,0 +1,29 @@
+/*
+ * u_debug_refcnt.h
+ *
+ *  Created on: Aug 17, 2010
+ *      Author: lb
+ */
+
+#ifndef U_DEBUG_REFCNT_H_
+#define U_DEBUG_REFCNT_H_
+
+#include <pipe/p_config.h>
+#include <pipe/p_state.h>
+
+#if defined(DEBUG) && (!defined(PIPE_OS_WINDOWS) || defined(PIPE_SUBSYSTEM_WINDOWS_USER))
+extern int debug_refcnt_state;
+
+void debug_reference_slowpath(const struct pipe_reference* p, void* get_desc, int change);
+
+static INLINE void debug_reference(const struct pipe_reference* p, void* get_desc, int change)
+{
+	if(debug_refcnt_state >= 0)
+		debug_reference_slowpath(p, get_desc, change);
+}
+#else
+static INLINE void debug_reference(const struct pipe_reference* p, void* get_desc, const char* op)
+{}
+#endif
+
+#endif /* U_DEBUG_REFCNT_H_ */