commit 75e7612437f65abe21689845b1856bb308c6cb81
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Nov 3 16:06:29 2021

    libstdc++: Print assertion messages to stderr [PR59675]
    
    This replaces the printf used by failed debug assertions with fprintf,
    so we can write to stderr. To avoid including <stdio.h> we call a new
    function exported from the library, which returns the stderr pointer.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/59675
            * acinclude.m4 (libtool_VERSION): Bump version.
            * config/abi/pre/gnu.ver (GLIBCXX_3.4.30): Add version and
            export new symbol.
            * configure: Regenerate.
            * include/bits/c++config (__replacement_assert): Use fprintf and
            write to stderr.
            * src/c++11/debug.cc (std::__stderr): Define.
            * testsuite/util/testsuite_abi.cc: Update latest version.

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 90ecc4a87a2..30a4abb98b3 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -3798,7 +3798,7 @@ changequote([,])dnl
 fi
 
 # For libtool versioning info, format is CURRENT:REVISION:AGE
-libtool_VERSION=6:29:0
+libtool_VERSION=6:30:0
 
 # Everything parsed; figure out what files and settings to use.
 case $enable_symvers in
diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index 5323c7f0604..3c59465ab9e 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -2397,6 +2397,12 @@ GLIBCXX_3.4.29 {
 
 } GLIBCXX_3.4.28;
 
+GLIBCXX_3.4.30 {
+
+    _ZSt8__stderrv;
+
+} GLIBCXX_3.4.29;
+
 # Symbols in the support library (libsupc++) have their own tag.
 CXXABI_1.3 {
 
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index c1aea827070..7dc7dcee029 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -74892,7 +74892,7 @@ $as_echo "$as_me: WARNING: === Symbol versioning will be disabled." >&2;}
 fi
 
 # For libtool versioning info, format is CURRENT:REVISION:AGE
-libtool_VERSION=6:29:0
+libtool_VERSION=6:30:0
 
 # Everything parsed; figure out what files and settings to use.
 case $enable_symvers in
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index a6495809671..75421731cae 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -531,8 +531,10 @@ namespace std
 		       const char* __function, const char* __condition)
   _GLIBCXX_NOEXCEPT
   {
-    __builtin_printf("%s:%d: %s: Assertion '%s' failed.\n", __file, __line,
-		     __function, __condition);
+    // Also avoid including <cstdio>.
+    extern void* __stderr() _GLIBCXX_NOEXCEPT;
+    __builtin_fprintf(__stderr(), "%s:%d: %s: Assertion '%s' failed.\n",
+		      __file, __line, __function, __condition);
     __builtin_abort();
   }
 }
diff --git a/libstdc++-v3/src/c++11/debug.cc b/libstdc++-v3/src/c++11/debug.cc
index 0128535135e..e79e49ea439 100644
--- a/libstdc++-v3/src/c++11/debug.cc
+++ b/libstdc++-v3/src/c++11/debug.cc
@@ -43,6 +43,12 @@
 
 #include "mutex_pool.h"
 
+namespace std
+{
+  // Used by std::__replacement_assert in <bits/c++config.h>.
+  void* __stderr() noexcept { return stderr; }
+}
+
 using namespace std;
 
 namespace
@@ -1202,4 +1208,5 @@ namespace __gnu_debug
                                     const char*) const;
 #endif
 
+
 } // namespace __gnu_debug
diff --git a/libstdc++-v3/testsuite/util/testsuite_abi.cc b/libstdc++-v3/testsuite/util/testsuite_abi.cc
index 3af5dc593c2..1ca7da4fcd0 100644
--- a/libstdc++-v3/testsuite/util/testsuite_abi.cc
+++ b/libstdc++-v3/testsuite/util/testsuite_abi.cc
@@ -210,6 +210,7 @@ check_version(symbol& test, bool added)
       known_versions.push_back("GLIBCXX_3.4.27");
       known_versions.push_back("GLIBCXX_3.4.28");
       known_versions.push_back("GLIBCXX_3.4.29");
+      known_versions.push_back("GLIBCXX_3.4.30");
       known_versions.push_back("GLIBCXX_LDBL_3.4.29");
       known_versions.push_back("GLIBCXX_IEEE128_3.4.29");
       known_versions.push_back("CXXABI_1.3");
@@ -245,7 +246,7 @@ 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_3.4.29"
+      bool latestp = (test.version_name == "GLIBCXX_3.4.30"
 	  // XXX remove next 3 lines when baselines have been regenerated
 	  // to include {IEEE128,LDBL} symbols:
 		     || test.version_name == "GLIBCXX_LDBL_3.4.29"