The attached patch eliminates the bootstrap failures in libstdc++-v3
of PR 54419 by having configure check for assembler support of the new
rdrnd opcode and defining _GLIBCXX_X86_RDRAND in config.h if supported.
Tested on x86_64-apple-darwin12 against the assembler from Xcode 4.4.1.
Okay for gcc trunk?
Jack
ps Regenerated config.h.in in libstdc++-v3 with...
autoheader -I. -I../config
and configure with...
autoconf -I. -I../config
libstdc++-v3/
2012-09-06 Ulrich Drepper <drep...@gmail.com>
Dominique d'Humieres <domi...@lps.ens.ft>
Jack Howarth <howa...@bromo.med.uc.edu>
PR bootstrap/54419
* configure.ac: Test for rdrnd support in assembler.
* src/c++11/random.cc: (__x86_rdrand): Depend on _GLIBCXX_X86_RDRAND.
(random_device::_M_init): Likewise.
(random_device::_M_getval): Likewise.
* configure: Regenerated.
* config.h.in: Regenerated.
Index: libstdc++-v3/src/c++11/random.cc
===================================================================
--- libstdc++-v3/src/c++11/random.cc (revision 191031)
+++ libstdc++-v3/src/c++11/random.cc (working copy)
@@ -50,7 +50,7 @@ namespace std _GLIBCXX_VISIBILITY(defaul
return __ret;
}
-#if defined __i386__ || defined __x86_64__
+#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
unsigned int
__attribute__ ((target("rdrnd")))
__x86_rdrand(void)
@@ -75,7 +75,7 @@ namespace std _GLIBCXX_VISIBILITY(defaul
if (token == "default")
{
-#if defined __i386__ || defined __x86_64__
+#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
unsigned int eax, ebx, ecx, edx;
// Check availability of cpuid and, for now at least, also the
// CPU signature for Intel's
@@ -118,7 +118,7 @@ namespace std _GLIBCXX_VISIBILITY(defaul
random_device::result_type
random_device::_M_getval()
{
-#if (defined __i386__ || defined __x86_64__)
+#if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND
if (! _M_file)
return __x86_rdrand();
#endif
Index: libstdc++-v3/configure.ac
===================================================================
--- libstdc++-v3/configure.ac (revision 191031)
+++ libstdc++-v3/configure.ac (working copy)
@@ -330,6 +330,18 @@ case "$target" in
esac
GLIBCXX_CONDITIONAL(GLIBCXX_LDBL_COMPAT, test $ac_ldbl_compat = yes)
+ac_cv_x86_rdrand=no
+case "$target" in
+ i?86-*-* | \
+ x86_64-*-*)
+ AC_TRY_COMPILE(, [asm("rdrand %eax");],
+ [ac_cv_x86_rdrand=yes], [ac_cv_x86_rdrand=no])
+esac
+if test $ac_cv_x86_rdrand = yes; then
+ AC_DEFINE(_GLIBCXX_X86_RDRAND, 1,
+ [ Defined if as can handle rdrand. ])
+fi
+
# This depends on GLIBCXX_ENABLE_SYMVERS and GLIBCXX_IS_NATIVE.
GLIBCXX_CONFIGURE_TESTSUITE
