[v3] fix bootstrap/54419

[Gerald Pfeifer]

On Sun, 9 Sep 2012, Jonathan Wakely wrote:
> I've committed the patch from
> http://gcc.gnu.org/ml/gcc-patches/2012-09/msg00466.html (with some
> fixes to the changelog entry)
> 
>     2012-09-09  Ulrich Drepper  <drepper@gmail.com>
>             Dominique d'Humieres  <dominiq@lps.ens.fr>
>             Jack Howarth  <howarth@bromo.med.uc.edu>
> 
>         PR bootstrap/54419
>         * acinclude.m4: Define GLIBCXX_CHECK_X86_RDRAND.
>         * configure.ac: Use GLIBCXX_CHECK_X86_RDRAND to test for rdrand
>         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.

amd64-unknown-freebsd8.3 doesn't like this, I'm afraid:

configure: visibility supported: yes
checking for rdrand support in assembler... eval: ${+...}: Bad substitution
gmake[2]: *** [configure-stage1-target-libstdc++-v3] Error 2

Note, this is BSD sh, not bash.  I'll admit that I had a look, and
did not find the culprit right away.

Gerald
-------------- next part --------------
commit 5202106d9ddcfd92989bfa6c11f7e9b2ea61cd10
Author: Jonathan Wakely <jwakely.gcc@gmail.com>
Date:   Sun Sep 9 17:28:50 2012 +0100

    2012-09-09  Ulrich Drepper  <drepper@gmail.com>
    	    Dominique d'Humieres  <dominiq@lps.ens.fr>
    	    Jack Howarth  <howarth@bromo.med.uc.edu>
    
    	PR bootstrap/54419
    	* acinclude.m4: Define GLIBCXX_CHECK_X86_RDRAND.
    	* configure.ac: Use GLIBCXX_CHECK_X86_RDRAND to test for rdrand
    	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.

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 1179407..267302d 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -3360,6 +3360,26 @@ AC_DEFUN([AC_LC_MESSAGES], [
 ])
 
 dnl
+dnl Check whether rdrand is supported in the assembler.
+AC_DEFUN([GLIBCXX_CHECK_X86_RDRAND], [
+  AC_MSG_CHECKING([for rdrand support in assembler])
+  AC_CACHE_VAL($ac_cv_x86_rdrand, [
+  ac_cv_x86_rdrand=no
+  case "$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 $ac_cv_x86_rdrand = yes; then
+    AC_DEFINE(_GLIBCXX_X86_RDRAND, 1,
+		[ Defined if as can handle rdrand. ])
+  fi
+  AC_MSG_RESULT($ac_cv_x86_rdrand)
+])
+
+dnl
 dnl Check whether get_nprocs is available in <sys/sysinfo.h>, and define _GLIBCXX_USE_GET_NPROCS.
 dnl
 AC_DEFUN([GLIBCXX_CHECK_GET_NPROCS], [
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 5c86bb9..555f380 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -330,6 +330,9 @@ case "$target" in
 esac
 GLIBCXX_CONDITIONAL(GLIBCXX_LDBL_COMPAT, test $ac_ldbl_compat = yes)
 
+# Check if assembler supports rdrand opcode.
+GLIBCXX_CHECK_X86_RDRAND
+
 # This depends on GLIBCXX_ENABLE_SYMVERS and GLIBCXX_IS_NATIVE.
 GLIBCXX_CONFIGURE_TESTSUITE
 
diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc
index 3b05318..4342df4 100644
--- a/libstdc++-v3/src/c++11/random.cc
+++ b/libstdc++-v3/src/c++11/random.cc
@@ -50,7 +50,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
       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(default)
 
     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(default)
   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