[Qemu-devel] [PATCH] avx2 configure: Disable if static build

[Aaron Lindsay]

This avoids a segfault like the following for at least some 4.8 versions
of gcc when configured with --static if avx2 instructions are also
enabled:

        Program received signal SIGSEGV, Segmentation fault.
        buffer_find_nonzero_offset_ifunc () at ./util/cutils.c:333
        333     {
        (gdb) bt
        #0  buffer_find_nonzero_offset_ifunc () at ./util/cutils.c:333
        #1  0x0000000000939c58 in __libc_start_main ()
        #2  0x0000000000419337 in _start ()

Signed-off-by: Aaron Lindsay <address@hidden>
---
 configure | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/configure b/configure
index 5ada56d..169aa88 100755
--- a/configure
+++ b/configure
@@ -1788,7 +1788,9 @@ fi
 ##########################################
 # avx2 optimization requirement check
 
-cat > $TMPC << EOF
+
+if test "$static" = "no" ; then
+  cat > $TMPC << EOF
 #pragma GCC push_options
 #pragma GCC target("avx2")
 #include <cpuid.h>
@@ -1801,12 +1803,13 @@ static void *bar_ifunc(void) {return (void*) bar;}
 int foo(void *a) __attribute__((ifunc("bar_ifunc")));
 int main(int argc, char *argv[]) { return foo(argv[0]);}
 EOF
-if compile_object "" ; then
-    if has readelf; then
-        if readelf --syms $TMPO 2>/dev/null |grep -q "IFUNC.*foo"; then
-            avx2_opt="yes"
-        fi
-    fi
+  if compile_object "" ; then
+      if has readelf; then
+          if readelf --syms $TMPO 2>/dev/null |grep -q "IFUNC.*foo"; then
+              avx2_opt="yes"
+          fi
+      fi
+  fi
 fi
 
 #########################################
-- 
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