Add the --disable-initial-exec-tls configure option.

Right now we always make our TLS use the initial-exec model if the compiler
supports it.  This change allows configure-time disabling of this setting, which
can be helpful when dynamically loading jemalloc is the only option.

1 files changed, 26 insertions, 6 deletions

diff --git a/configure.ac b/configure.ac
index e45970e..ba0b694 100644
--- a/configure.ac
+++ b/configure.ac
@@ -733,12 +733,9 @@ JE_COMPILABLE([tls_model attribute], [],
                foo = 0;],
               [je_cv_tls_model])
 JE_CFLAGS_RESTORE()
-if test "x${je_cv_tls_model}" = "xyes" ; then
-  AC_DEFINE([JEMALLOC_TLS_MODEL],
-            [__attribute__((tls_model("initial-exec")))])
-else
-  AC_DEFINE([JEMALLOC_TLS_MODEL], [ ])
-fi
+dnl (Setting of JEMALLOC_TLS_MODEL is done later, after we've checked for
+dnl --disable-initial-exec-tls)
+
 dnl Check for alloc_size attribute support.
 JE_CFLAGS_SAVE()
 JE_CFLAGS_ADD([-Werror])
@@ -1994,6 +1991,29 @@ if test "x${enable_zone_allocator}" = "x1" ; then
 fi
 
 dnl ============================================================================
+dnl Use initial-exec TLS by default.
+AC_ARG_ENABLE([initial-exec-tls],
+  [AS_HELP_STRING([--disable-initial-exec-tls],
+                  [Disable the initial-exec tls model])],
+[if test "x$enable_initial_exec_tls" = "xno" ; then
+  enable_initial_exec_tls="0"
+else
+  enable_initial_exec_tls="1"
+fi
+],
+[enable_initial_exec_tls="1"]
+)
+AC_SUBST([enable_initial_exec_tls])
+
+if test "x${je_cv_tls_model}" = "xyes" -a \
+       "x${enable_initial_exec_tls}" = "x1" ; then
+  AC_DEFINE([JEMALLOC_TLS_MODEL],
+            [__attribute__((tls_model("initial-exec")))])
+else
+  AC_DEFINE([JEMALLOC_TLS_MODEL], [ ])
+fi
+
+dnl ============================================================================
 dnl Enable background threads if possible.
 
 if test "x${have_pthread}" = "x1" -a "x${have_dlsym}" = "x1" \