From 0bebaed0acd3b07d2d85e0269344f628a5d9e575 Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Fri, 16 Oct 2015 15:13:51 +0100
Subject: [PATCH] Eo do: use the __thread directive when available to manage
 call stack.

This is faster in most cases, and to be honest, should be much faster
than it is. I don't understand why there's no better directive to mark a
variable as *really* important thread storage that is used all the time.
---
 configure.ac    | 15 +++++++++++++++
 src/lib/eo/eo.c | 14 +++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 5ecbcac4f6..f0980adf7b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -984,6 +984,20 @@ if test "x${efl_have_threads}" = "xno"; then
    CFOPT_WARNING="xyes"
 fi
 
+AC_COMPILE_IFELSE(
+   [AC_LANG_PROGRAM(
+       [[ ]],
+       [[
+        static __thread int a = 0;
+       ]])],
+   [have_thread_specifier="yes"],
+   [have_thread_specifier="no"])
+AC_MSG_CHECKING([for __thread specifier])
+AC_MSG_RESULT([${have_thread_specifier}])
+if test "x${have_thread_specifier}" = "xyes" ; then
+    AC_DEFINE([HAVE_THREAD_SPECIFIER], [1], [Have the __thread specifier])
+fi
+
 EFL_ADD_PUBLIC_LIBS([EINA], [${EFL_PTHREAD_LIBS}])
 EFL_ADD_CFLAGS([EINA], [${EFL_PTHREAD_CFLAGS}])
 
@@ -4868,6 +4882,7 @@ EFL_ADD_FEATURE([thread], [spinlocks], [${efl_have_spinlock}])
 EFL_ADD_FEATURE([thread], [barrier], [${efl_have_pthread_barrier}])
 EFL_ADD_FEATURE([thread], [affinity], [${efl_have_setaffinity}])
 EFL_ADD_FEATURE([thread], [setname], [${efl_have_setname}])
+EFL_ADD_FEATURE([thread], [__thread], [${have_thread_specifier}])
 
 echo
 echo
diff --git a/src/lib/eo/eo.c b/src/lib/eo/eo.c
index 4b33c2c111..fd1fc2a3a3 100644
--- a/src/lib/eo/eo.c
+++ b/src/lib/eo/eo.c
@@ -375,6 +375,13 @@ _eo_call_stack_free(void *ptr)
    free(stack);
 }
 
+#ifdef HAVE_THREAD_SPECIFIER
+static __thread Eo_Call_Stack *_eo_thread_stack = NULL;
+
+#define _EO_CALL_STACK_GET() ((_eo_thread_stack) ? _eo_thread_stack : (_eo_thread_stack = _eo_call_stack_create()))
+
+#else
+
 static Eo_Call_Stack *main_loop_stack = NULL;
 
 #define _EO_CALL_STACK_GET() ((EINA_LIKELY(eina_main_loop_is())) ? main_loop_stack : _eo_call_stack_get_thread())
@@ -382,9 +389,7 @@ static Eo_Call_Stack *main_loop_stack = NULL;
 static inline Eo_Call_Stack *
 _eo_call_stack_get_thread(void)
 {
-   Eo_Call_Stack *stack;
-
-   stack = eina_tls_get(_eo_call_stack_key);
+   Eo_Call_Stack *stack = eina_tls_get(_eo_call_stack_key);
 
    if (stack) return stack;
 
@@ -393,6 +398,7 @@ _eo_call_stack_get_thread(void)
 
    return stack;
 }
+#endif
 
 EAPI EINA_CONST void *
 _eo_stack_get(void)
@@ -1826,12 +1832,14 @@ eo_init(void)
           }
      }
 
+#ifndef HAVE_THREAD_SPECIFIER
    main_loop_stack = _eo_call_stack_create();
    if (!main_loop_stack)
      {
         EINA_LOG_ERR("Could not alloc eo call stack.");
         return EINA_FALSE;
      }
+#endif
 
    return EINA_TRUE;
 }