[Qemu-devel] [PATCH v3 1.0] configure: tighten pie toolchain support test for tls variables

[Avi Kivity <avi@redhat.com>]

Some toolchains don't support pie properly when tls variables are
in use.  Disallow pie when such toolchains are detected.

Signed-off-by: Avi Kivity <avi@redhat.com>
---

v3: only check __thread on Linux, where we require it, and where the
    toolchain fails

v2: give tls_var a type; avoids invisible warning

 configure |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/configure b/configure
index 75e1f10..1a2c55f 100755
--- a/configure
+++ b/configure
@@ -1120,7 +1120,17 @@ fi
 
 if test "$pie" != "no" ; then
   cat > $TMPC << EOF
-int main(void) { return 0; }
+
+#ifdef __linux__
+#  define THREAD __thread
+#else
+#  define THREAD
+#endif
+
+static THREAD int tls_var;
+
+int main(void) { return tls_var; }
+
 EOF
   if compile_prog "-fPIE -DPIE" "-pie"; then
     QEMU_CFLAGS="-fPIE -DPIE $QEMU_CFLAGS"
-- 
1.7.7.1