[Mesa-dev] [PATCH v3 1/2] configure.ac: Enable GLX_USE_TLS if possible.

[zhigang.gong at linux.intel.com]

From: Zhigang Gong <zhigang.gong at linux.intel.com>

If the system support tls, we prefer to enable it by default
just as xserver does. Actually, the checking code is copied
from xserver/configure.ac.
According to nobled's suggestion, move the checking before
enable_asm. As if tls_model is not supported, then asm may
can't work correctly. Then we check the tls model first,
and if doesn't support it, we need to disable the asm code.
Here is the reference:
https://bugs.freedesktop.org/show_bug.cgi?id=35268

Signed-off-by: Zhigang Gong <zhigang.gong at linux.intel.com>
Reviewed-by: Dan Nicholson <dbn.lists at gmail.com>
---
 acinclude.m4 |   41 +++++++++++++++++++++++++++++++++++++++++
 configure.ac |   25 ++++++++++++++++++++++---
 2 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index a5b389d..23805f3 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -117,3 +117,44 @@ if test "$enable_pic" != no; then
 fi
 AC_SUBST([PIC_FLAGS])
 ])# MESA_PIC_FLAGS
+
+dnl TLS detection
+AC_DEFUN([MESA_TLS],
+[AC_MSG_CHECKING(for thread local storage (TLS) support)
+AC_CACHE_VAL(ac_cv_tls, [
+    ac_cv_tls=none
+    keywords="__thread __declspec(thread)"
+    for kw in $keywords ; do
+        AC_TRY_COMPILE([int $kw test;], [], ac_cv_tls=$kw)
+    done
+])
+AC_MSG_RESULT($ac_cv_tls)
+
+if test "$ac_cv_tls" != "none"; then
+    STRICT_CFLAGS="-pedantic -Werror"
+    # Add -Werror=attributes if supported (gcc 4.2 & later)
+    AC_MSG_CHECKING([if $CC supports -Werror=attributes])
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS $STRICT_CFLAGS -Werror=attributes"
+    AC_TRY_COMPILE([int test;], [],
+                   [STRICT_CFLAGS="$STRICT_CFLAGS -Werror=attributes"
+                    AC_MSG_RESULT([yes])],
+                   [AC_MSG_RESULT([no])])
+    CFLAGS="$save_CFLAGS $STRICT_CFLAGS"
+
+    AC_MSG_CHECKING(for tls_model attribute support)
+    AC_CACHE_VAL(ac_cv_tls_model, [
+        AC_TRY_COMPILE([int $ac_cv_tls __attribute__((tls_model("initial-exec"))) test;], [],
+                       ac_cv_tls_model=yes, ac_cv_tls_model=no)
+    ])
+    AC_MSG_RESULT($ac_cv_tls_model)
+
+    if test "x$ac_cv_tls_model" = "xyes" ; then
+        TLS=$ac_cv_tls' __attribute__((tls_model(\"initial-exec\")))'
+    else
+        TLS=$ac_cv_tls
+    fi
+    DEFINES="$DEFINES -DTLS=\"$TLS\""
+    CFLAGS="$save_CFLAGS"
+fi
+])
diff --git a/configure.ac b/configure.ac
index b2b1ab8..3226a09 100644
--- a/configure.ac
+++ b/configure.ac
@@ -433,6 +433,11 @@ AC_SUBST([VG_LIB_GLOB])
 AC_SUBST([GLAPI_LIB_GLOB])
 
 dnl
+dnl Check tls model support
+dnl
+MESA_TLS
+
+dnl
 dnl Arch/platform-specific settings
 dnl
 AC_ARG_ENABLE([asm],
@@ -446,6 +451,14 @@ ASM_FLAGS=""
 MESA_ASM_SOURCES=""
 GLAPI_ASM_SOURCES=""
 AC_MSG_CHECKING([whether to enable assembly])
+
+if test "x$ac_cv_tls_model" = "xno" ; then
+dnl
+dnl If tls model is not supported, disable asm.
+dnl
+    enable_asm=no
+fi
+
 test "x$enable_asm" = xno && AC_MSG_RESULT([no])
 # disable if cross compiling on x86/x86_64 since we must run gen_matypes
 if test "x$enable_asm" = xyes && test "x$cross_compiling" = xyes; then
@@ -1102,9 +1115,15 @@ dnl
 
 AC_ARG_ENABLE([glx-tls],
     [AS_HELP_STRING([--enable-glx-tls],
-        [enable TLS support in GLX @<:@default=disabled@:>@])],
-    [GLX_USE_TLS="$enableval"],
-    [GLX_USE_TLS=no])
+        [enable TLS support in GLX @<:@default=auto@:>@])],
+    [GLX_USE_TLS=$enableval
+     if test "x$GLX_USE_TLS" = "xyes" && test "${ac_cv_tls}" = "none" ; then
+        AC_MSG_ERROR([GLX with TLS support requested, but the compiler does not support it.])
+     fi],
+    [GLX_USE_TLS=no
+     if test "${ac_cv_tls}" != "none" ; then
+        GLX_USE_TLS=yes
+     fi])
 AC_SUBST(GLX_TLS, ${GLX_USE_TLS})
 
 AS_IF([test "x$GLX_USE_TLS" = xyes],
-- 
1.7.4.4