From ecebc263f5b03550e27df0d1068340b61621fa93 Mon Sep 17 00:00:00 2001
From: Erik Faye-Lund <erik.faye-lund@collabora.com>
Date: Tue, 24 Nov 2020 23:35:08 +0100
Subject: [PATCH] Revert "util: Add helpers for various one-time-init patters"

This reverts commit bda4d6e0d01116db59a0a03b0c703a7af6e11949.

Acked-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7760>
---
 src/util/debug.h   | 61 ----------------------------------------------
 src/util/u_debug.h | 33 +++++++++++++++++++++----
 2 files changed, 28 insertions(+), 66 deletions(-)

diff --git a/src/util/debug.h b/src/util/debug.h
index e6a53e2fdec..bbcc1975545 100644
--- a/src/util/debug.h
+++ b/src/util/debug.h
@@ -27,8 +27,6 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-#include "util/simple_mtx.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -52,63 +50,4 @@ env_var_as_unsigned(const char *var_name, unsigned default_value);
 } /* extern C */
 #endif
 
-/**
- * Helper for arbitrary one-time initialization, with additional locking
- * to ensure the initialization only happens once (and to make tools like
- * helgrind happy).
- */
-#define do_once for( \
-      struct __do_once_data *__d = ({                 \
-         static struct __do_once_data __sd = {        \
-               .lock = _SIMPLE_MTX_INITIALIZER_NP,    \
-               .done = false,                         \
-         };                                           \
-         simple_mtx_lock(&__sd.lock);                 \
-         &__sd;                                       \
-      });                                             \
-      ({                                              \
-         if (__d->done)                               \
-            simple_mtx_unlock(&__d->lock);            \
-         !__d->done;                                  \
-      });                                             \
-      __d->done = true)
-
-struct __do_once_data {
-   simple_mtx_t lock;
-   bool done;
-};
-
-/**
- * Helper for one-time debug value from env-var, and other similar cases,
- * where the expression is expected to return the same value each time.
- *
- * This has additional locking, compared to open-coding the initialization,
- * to make tools like helgrind happy.
- */
-#define get_once(__expr) ({                           \
-      static __typeof__(__expr) __val;                \
-      do_once {                                       \
-         __val = __expr;                              \
-      }                                               \
-      __val;                                          \
-   })
-
-/**
- * Alternative version of get_once() which has no locking in release builds,
- * suitable for hot-paths.
- */
-#ifndef NDEBUG
-#define get_once_nolock(__expr) ({                    \
-      static bool __once;                             \
-      static __typeof__(__expr) __val;                \
-      if (!__once) {                                  \
-         __val = __expr;                              \
-         __once = true;                               \
-      }                                               \
-      __val;                                          \
-   })
-#else
-#define get_once_nolock(__expr) get_once(__expr)
-#endif
-
 #endif /* _UTIL_DEBUG_H */
diff --git a/src/util/u_debug.h b/src/util/u_debug.h
index d4f77c61251..fc06c582b0d 100644
--- a/src/util/u_debug.h
+++ b/src/util/u_debug.h
@@ -40,7 +40,6 @@
 
 #include <stdarg.h>
 #include <string.h>
-#include "util/debug.h"
 #include "util/os_misc.h"
 #include "util/detect_os.h"
 #include "util/macros.h"
@@ -408,28 +407,52 @@ debug_get_flags_option(const char *name,
 static const char * \
 debug_get_option_ ## suffix (void) \
 { \
-   return get_once_nolock(debug_get_option(name, dfault)); \
+   static bool first = true; \
+   static const char * value; \
+   if (first) { \
+      first = false; \
+      value = debug_get_option(name, dfault); \
+   } \
+   return value; \
 }
 
 #define DEBUG_GET_ONCE_BOOL_OPTION(sufix, name, dfault) \
 static bool \
 debug_get_option_ ## sufix (void) \
 { \
-   return get_once_nolock(debug_get_bool_option(name, dfault)); \
+   static bool first = true; \
+   static bool value; \
+   if (first) { \
+      first = false; \
+      value = debug_get_bool_option(name, dfault); \
+   } \
+   return value; \
 }
 
 #define DEBUG_GET_ONCE_NUM_OPTION(sufix, name, dfault) \
 static long \
 debug_get_option_ ## sufix (void) \
 { \
-   return get_once_nolock(debug_get_num_option(name, dfault)); \
+   static bool first = true; \
+   static long value; \
+   if (first) { \
+      first = false; \
+      value = debug_get_num_option(name, dfault); \
+   } \
+   return value; \
 }
 
 #define DEBUG_GET_ONCE_FLAGS_OPTION(sufix, name, flags, dfault) \
 static unsigned long \
 debug_get_option_ ## sufix (void) \
 { \
-   return get_once_nolock(debug_get_flags_option(name, flags, dfault)); \
+   static bool first = true; \
+   static unsigned long value; \
+   if (first) { \
+      first = false; \
+      value = debug_get_flags_option(name, flags, dfault); \
+   } \
+   return value; \
 }