PR libstdc++/67578 Implement non-trivial std::random_device::entropy

2017-05-23  Xi Ruoyao  <ryxi@stu.xidian.edu.cn>
	    Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/67578
	* acinclude.m4: Bump libtool_VERSION.
	* config/abi/pre/gnu.ver: Create GLIBCXX_3.4.24 with new symbol.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Add test for <linux/random.h>.
	* doc/xml/manual/abi.xml: Document new library version.
	* include/bits/random.h (random_device::entropy)
	[_GLIBCXX_USE_RANDOM_TR1]: Add call to new _M_getentropy member.
	(random_device::_M_getentropy): Declare.
	* src/c++11/random.cc (random_device::_M_getentropy): Define.
	* testsuite/util/testsuite_abi.cc: Add GLIBCXX_3.4.24 to known
	versions, and make it the latest version.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@248374 138bc75d-0d04-0410-961f-82ee72b054a4

10 files changed, 78 insertions, 6 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 5b34ccf1166..536e710f1ef 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,4 +1,21 @@
 2017-05-23  Xi Ruoyao  <ryxi@stu.xidian.edu.cn>
+	    Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/67578
+	* acinclude.m4: Bump libtool_VERSION.
+	* config/abi/pre/gnu.ver: Create GLIBCXX_3.4.24 with new symbol.
+	* config.h.in: Regenerate.
+	* configure: Regenerate.
+	* configure.ac: Add test for <linux/random.h>.
+	* doc/xml/manual/abi.xml: Document new library version.
+	* include/bits/random.h (random_device::entropy)
+	[_GLIBCXX_USE_RANDOM_TR1]: Add call to new _M_getentropy member.
+	(random_device::_M_getentropy): Declare.
+	* src/c++11/random.cc (random_device::_M_getentropy): Define.
+	* testsuite/util/testsuite_abi.cc: Add GLIBCXX_3.4.24 to known
+	versions, and make it the latest version.
+
+2017-05-23  Xi Ruoyao  <ryxi@stu.xidian.edu.cn>
 
 	PR libstdc++/67214
 	* include/bits/locale_facets.tcc (num_get::_M_extract_int): Add
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 61c8cb29084..baeea67c459 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -3750,7 +3750,7 @@ changequote([,])dnl
 fi
 
 # For libtool versioning info, format is CURRENT:REVISION:AGE
-libtool_VERSION=6:23:0
+libtool_VERSION=6:24:0
 
 # Everything parsed; figure out what files and settings to use.
 case $enable_symvers in
diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in
index f1527d9938b..e31e054c024 100644
--- a/libstdc++-v3/config.h.in
+++ b/libstdc++-v3/config.h.in
@@ -267,6 +267,9 @@
 /* Define if futex syscall is available. */
 #undef HAVE_LINUX_FUTEX
 
+/* Define to 1 if you have the <linux/random.h> header file. */
+#undef HAVE_LINUX_RANDOM_H
+
 /* Define to 1 if you have the <locale.h> header file. */
 #undef HAVE_LOCALE_H
 
diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index 268fb9479a9..48e2ec870fc 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1967,6 +1967,13 @@ GLIBCXX_3.4.23 {
 
 } GLIBCXX_3.4.22;
 
+GLIBCXX_3.4.24 {
+
+    # std::random_device::_M_getentropy() const
+    _ZNKSt13random_device13_M_getentropyEv;
+
+} GLIBCXX_3.4.23;
+
 # Symbols in the support library (libsupc++) have their own tag.
 CXXABI_1.3 {
 
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 7c10c9e42df..282b4617db8 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -21795,7 +21795,7 @@ for ac_header in endian.h execinfo.h float.h fp.h ieeefp.h inttypes.h \
 locale.h machine/endian.h machine/param.h nan.h stdint.h stdlib.h string.h \
 strings.h sys/ipc.h sys/isa_defs.h sys/machine.h sys/param.h \
 sys/resource.h sys/sem.h sys/stat.h sys/time.h sys/types.h unistd.h \
-wchar.h wctype.h
+wchar.h wctype.h linux/random.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -79268,7 +79268,7 @@ $as_echo "$as_me: WARNING: === Symbol versioning will be disabled." >&2;}
 fi
 
 # For libtool versioning info, format is CURRENT:REVISION:AGE
-libtool_VERSION=6:23:0
+libtool_VERSION=6:24:0
 
 # Everything parsed; figure out what files and settings to use.
 case $enable_symvers in
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 8e973503be0..270dcbaf723 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -237,7 +237,7 @@ AC_CHECK_HEADERS([endian.h execinfo.h float.h fp.h ieeefp.h inttypes.h \
 locale.h machine/endian.h machine/param.h nan.h stdint.h stdlib.h string.h \
 strings.h sys/ipc.h sys/isa_defs.h sys/machine.h sys/param.h \
 sys/resource.h sys/sem.h sys/stat.h sys/time.h sys/types.h unistd.h \
-wchar.h wctype.h])
+wchar.h wctype.h linux/random.h])
 
 # Only do link tests if native. Else, hardcode.
 if $GLIBCXX_IS_NATIVE; then
diff --git a/libstdc++-v3/doc/xml/manual/abi.xml b/libstdc++-v3/doc/xml/manual/abi.xml
index d086d9ecf2d..d17f06e25fb 100644
--- a/libstdc++-v3/doc/xml/manual/abi.xml
+++ b/libstdc++-v3/doc/xml/manual/abi.xml
@@ -266,6 +266,7 @@ compatible.
     <listitem><para>GCC 5.1.0: libstdc++.so.6.0.21</para></listitem>
     <listitem><para>GCC 6.1.0: libstdc++.so.6.0.22</para></listitem>
     <listitem><para>GCC 7.1.0: libstdc++.so.6.0.23</para></listitem>
+    <listitem><para>GCC 8.0.0: libstdc++.so.6.0.24</para></listitem>
     </itemizedlist>
     <para>
       Note 1: Error should be libstdc++.so.3.0.3.
@@ -334,6 +335,7 @@ compatible.
     <listitem><para>GCC 5.1.0: GLIBCXX_3.4.21, CXXABI_1.3.9</para></listitem>
     <listitem><para>GCC 6.1.0: GLIBCXX_3.4.22, CXXABI_1.3.10</para></listitem>
     <listitem><para>GCC 7.1.0: GLIBCXX_3.4.23, CXXABI_1.3.11</para></listitem>
+    <listitem><para>GCC 8.0.0: GLIBCXX_3.4.24, CXXABI_1.3.11</para></listitem>
     </itemizedlist>
     </listitem>
 
diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index d39cc3e0666..bb761ec8fb0 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -1603,7 +1603,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
     double
     entropy() const noexcept
-    { return 0.0; }
+    {
+#ifdef _GLIBCXX_USE_RANDOM_TR1
+      return this->_M_getentropy();
+#else
+      return 0.0;
+#endif
+    }
 
     result_type
     operator()()
@@ -1627,6 +1633,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
     result_type _M_getval();
     result_type _M_getval_pretr1();
+    double _M_getentropy() const noexcept;
 
     union
     {
diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc
index df798742fce..5011cf2bb6b 100644
--- a/libstdc++-v3/src/c++11/random.cc
+++ b/libstdc++-v3/src/c++11/random.cc
@@ -38,6 +38,14 @@
 # include <unistd.h>
 #endif
 
+#ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
+# include <sys/ioctl.h>
+#endif
+
+#ifdef _GLIBCXX_HAVE_LINUX_RANDOM_H
+# include <linux/random.h>
+#endif
+
 namespace std _GLIBCXX_VISIBILITY(default)
 {
   namespace
@@ -161,6 +169,33 @@ namespace std _GLIBCXX_VISIBILITY(default)
     return _M_mt();
   }
 
+  double
+  random_device::_M_getentropy() const noexcept
+  {
+#if defined _GLIBCXX_HAVE_SYS_IOCTL_H && defined RNDGETENTCNT
+    if (!_M_file)
+      return 0.0;
+
+    const int fd = fileno(static_cast<FILE*>(_M_file));
+    if (fd < 0)
+      return 0.0;
+
+    int ent;
+    if (ioctl(fd, RNDGETENTCNT, &ent) < 0)
+      return 0.0;
+
+    if (ent < 0)
+      return 0.0;
+
+    if (static_cast<unsigned>(ent) > sizeof(result_type) * 8)
+      return static_cast<double>(sizeof(result_type) * 8);
+
+    return static_cast<double>(ent);
+#else
+    return 0.0;
+#endif
+  }
+
   template class mersenne_twister_engine<
     uint_fast32_t,
     32, 624, 397, 31,
diff --git a/libstdc++-v3/testsuite/util/testsuite_abi.cc b/libstdc++-v3/testsuite/util/testsuite_abi.cc
index f5fc594d194..ee7572ea244 100644
--- a/libstdc++-v3/testsuite/util/testsuite_abi.cc
+++ b/libstdc++-v3/testsuite/util/testsuite_abi.cc
@@ -204,6 +204,7 @@ check_version(symbol& test, bool added)
       known_versions.push_back("GLIBCXX_LDBL_3.4.21");
       known_versions.push_back("GLIBCXX_3.4.22");
       known_versions.push_back("GLIBCXX_3.4.23");
+      known_versions.push_back("GLIBCXX_3.4.24");
       known_versions.push_back("CXXABI_1.3");
       known_versions.push_back("CXXABI_LDBL_1.3");
       known_versions.push_back("CXXABI_1.3.1");
@@ -234,7 +235,7 @@ check_version(symbol& test, bool added)
 	test.version_status = symbol::incompatible;
 
       // Check that added symbols are added in the latest pre-release version.
-      bool latestp = (test.version_name == "GLIBCXX_3.4.23"
+      bool latestp = (test.version_name == "GLIBCXX_3.4.24"
 		     || test.version_name == "CXXABI_1.3.11"
 		     || test.version_name == "CXXABI_FLOAT128"
 		     || test.version_name == "CXXABI_TM_1");