[v2] Add test case for C++11 thread_local support

On 10/06/2015 09:09 PM, Carlos O'Donell wrote:
> On 10/06/2015 07:18 AM, Florian Weimer wrote:
>> I went with a check on an internal libstdc++ macro.  The test now
>> remains UNSUPPORTED if the compiler supports it, but libstdc++ has
>> emuluation only (based on its header file).
> 
> Did you attach the wrong patch? This v2 patch still has a contributed-by
> line and no such libstdc++ macro check?

Sorry, must have forgotten to regenerate it before manually editing it
before submission.

Florian

On 10/06/2015 03:13 PM, Florian Weimer wrote:
> On 10/06/2015 09:09 PM, Carlos O'Donell wrote:
>> > On 10/06/2015 07:18 AM, Florian Weimer wrote:
>>> >> I went with a check on an internal libstdc++ macro.  The test now
>>> >> remains UNSUPPORTED if the compiler supports it, but libstdc++ has
>>> >> emuluation only (based on its header file).
>> > 
>> > Did you attach the wrong patch? This v2 patch still has a contributed-by
>> > line and no such libstdc++ macro check?
> Sorry, must have forgotten to regenerate it before manually editing it
> before submission.

Perfect. Please check this in. I'm happy to have some early warning with
respect to C++ integration issues in glibc, particularly given how much
support you need from glibc to get it right.
 
> 0001-Add-a-test-case-for-C-11-thread_local-support.patch
> 
> 
> 2015-10-06  Florian Weimer  <fweimer@redhat.com>
> 
> 	* configure.ac (libc_cv_cxx_thread_local): Define.
> 	* configure: Regenerate.
> 	* config.make.in (have-cxx-thread_local): Define.
> 	* nptl/Makefile (CFLAGS-tst-thread_local1.o):
> 	(LDLIBS-tst-thread_local1): Define.
> 	(tests): Add tst-thread_local1.
> 	[have-cxx-thread_local != yes] (tests-unsupported): Add
> 	tst-thread_local1.
> 	* nptl/tst-thread_local1.cc: New file.
> 
> diff --git a/config.make.in b/config.make.in
> index bea371d..839d86f 100644
> --- a/config.make.in
> +++ b/config.make.in
> @@ -68,6 +68,7 @@ bind-now = @bindnow@
>  have-hash-style = @libc_cv_hashstyle@
>  use-default-link = @use_default_link@
>  output-format = @libc_cv_output_format@
> +have-cxx-thread_local = @libc_cv_cxx_thread_local@
>  
>  static-libgcc = @libc_cv_gcc_static_libgcc@
>  
> diff --git a/configure.ac b/configure.ac
> index 95d700e..75a3a77 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1982,6 +1982,39 @@ if test $libc_cv_builtin_trap = yes; then
>    AC_DEFINE([HAVE_BUILTIN_TRAP])
>  fi
>  
> +dnl C++ feature tests.
> +AC_LANG_PUSH([C++])
> +
> +AC_CACHE_CHECK([whether the C++ compiler supports thread_local],
> +	       libc_cv_cxx_thread_local, [
> +old_CXXFLAGS="$CXXFLAGS"
> +CXXFLAGS="$CXXFLAGS -std=gnu++11"
> +AC_COMPILE_IFELSE([AC_LANG_SOURCE([
> +#include <thread>
> +
> +// Compiler support.
> +struct S
> +{
> +  S ();
> +  ~S ();
> +};
> +thread_local S s;
> +S * get () { return &s; }
> +
> +// libstdc++ support.
> +#ifndef _GLIBCXX_HAVE___CXA_THREAD_ATEXIT_IMPL
> +#error __cxa_thread_atexit_impl not supported
> +#endif
> +])],
> +	       [libc_cv_cxx_thread_local=yes],
> +	       [libc_cv_cxx_thread_local=no])
> +CXXFLAGS="$old_CXXFLAGS"
> +])
> +AC_SUBST(libc_cv_cxx_thread_local)
> +
> +AC_LANG_POP([C++])
> +dnl End of C++ feature tests.
> +
>  ### End of automated tests.
>  ### Now run sysdeps configure fragments.
>  
> diff --git a/nptl/Makefile b/nptl/Makefile
> index aaca0a4..f3de49b 100644
> --- a/nptl/Makefile
> +++ b/nptl/Makefile
> @@ -212,6 +212,8 @@ CFLAGS-recvfrom.c = -fexceptions -fasynchronous-unwind-tables
>  CFLAGS-pt-system.c = -fexceptions
>  
>  LDLIBS-tst-once5 = -lstdc++
> +CFLAGS-tst-thread_local1.o = -std=gnu++11
> +LDLIBS-tst-thread_local1 = -lstdc++
>  
>  tests = tst-typesizes \
>  	tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
> @@ -283,7 +285,8 @@ tests = tst-typesizes \
>  	tst-getpid3 \
>  	tst-setuid3 \
>  	tst-initializers1 $(addprefix tst-initializers1-,c89 gnu89 c99 gnu99) \
> -	tst-bad-schedattr
> +	tst-bad-schedattr \
> +	tst-thread_local1
>  xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \
>  	tst-mutexpp1 tst-mutexpp6 tst-mutexpp10
>  test-srcs = tst-oddstacklimit
> @@ -403,6 +406,10 @@ ifeq (,$(CXX))
>  # These tests require a C++ compiler and runtime.
>  tests-unsupported += tst-cancel24 tst-cancel24-static tst-once5
>  endif
> +# These tests require a C++ compiler and runtime with thread_local support.
> +ifneq ($(have-cxx-thread_local),yes)
> +tests-unsupported += tst-thread_local1
> +endif
>  
>  include ../Rules
>  
> diff --git a/nptl/tst-thread_local1.cc b/nptl/tst-thread_local1.cc
> new file mode 100644
> index 0000000..133cc27
> --- /dev/null
> +++ b/nptl/tst-thread_local1.cc
> @@ -0,0 +1,199 @@
> +/* Test basic thread_local support.
> +   Copyright (C) 2015 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <errno.h>
> +#include <pthread.h>
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include <functional>
> +#include <string>
> +#include <thread>
> +
> +struct counter
> +{
> +  int constructed {};
> +  int destructed {};
> +
> +  void reset ();
> +};
> +
> +void
> +counter::reset ()
> +{
> +  constructed = 0;
> +  destructed = 0;
> +}
> +
> +static std::string
> +to_string (const counter &c)
> +{
> +  char buf[128];
> +  snprintf (buf, sizeof (buf), "%d/%d",
> +            c.constructed, c.destructed);
> +  return buf;
> +}
> +
> +template <counter *Counter>
> +struct counting
> +{
> +  counting () __attribute__ ((noinline, noclone));
> +  ~counting () __attribute__ ((noinline, noclone));
> +  void operation () __attribute__ ((noinline, noclone));
> +};
> +
> +template<counter *Counter>
> +__attribute__ ((noinline, noclone))
> +counting<Counter>::counting ()
> +{
> +  ++Counter->constructed;
> +}
> +
> +template<counter *Counter>
> +__attribute__ ((noinline, noclone))
> +counting<Counter>::~counting ()
> +{
> +  ++Counter->destructed;
> +}
> +
> +template<counter *Counter>
> +void __attribute__ ((noinline, noclone))
> +counting<Counter>::operation ()
> +{
> +  // Optimization barrier.
> +  asm ("");
> +}
> +
> +static counter counter_static;
> +static counter counter_anonymous_namespace;
> +static counter counter_extern;
> +static counter counter_function_local;
> +static bool errors (false);
> +
> +static std::string
> +all_counters ()
> +{
> +  return to_string (counter_static)
> +    + ' ' + to_string (counter_anonymous_namespace)
> +    + ' ' + to_string (counter_extern)
> +    + ' ' + to_string (counter_function_local);
> +}
> +
> +static void
> +check_counters (const char *name, const char *expected)
> +{
> +  std::string actual{all_counters ()};
> +  if (actual != expected)
> +    {
> +      printf ("error: %s: (%s) != (%s)\n",
> +              name, actual.c_str (), expected);
> +      errors = true;
> +    }
> +}
> +
> +static void
> +reset_all ()
> +{
> +  counter_static.reset ();
> +  counter_anonymous_namespace.reset ();
> +  counter_extern.reset ();
> +  counter_function_local.reset ();
> +}
> +
> +static thread_local counting<&counter_static> counting_static;
> +namespace {
> +  thread_local counting<&counter_anonymous_namespace>
> +    counting_anonymous_namespace;
> +}
> +extern thread_local counting<&counter_extern> counting_extern;
> +thread_local counting<&counter_extern> counting_extern;
> +
> +static void *
> +thread_without_access (void *)
> +{
> +  return nullptr;
> +}
> +
> +static void *
> +thread_with_access (void *)
> +{
> +  thread_local counting<&counter_function_local> counting_function_local;
> +  counting_function_local.operation ();
> +  check_counters ("early in thread_with_access", "0/0 0/0 0/0 1/0");
> +  counting_static.operation ();
> +  counting_anonymous_namespace.operation ();
> +  counting_extern.operation ();
> +  check_counters ("in thread_with_access", "1/0 1/0 1/0 1/0");
> +  return nullptr;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  std::function<void (void *(void *))> do_pthread =
> +    [](void *(func) (void *))
> +    {
> +      pthread_t thr;
> +      int ret = pthread_create (&thr, nullptr, func, nullptr);
> +      if (ret != 0)
> +        {
> +          errno = ret;
> +          printf ("error: pthread_create: %m\n");
> +          errors = true;
> +          return;
> +        }
> +      ret = pthread_join (thr, nullptr);
> +      if (ret != 0)
> +        {
> +          errno = ret;
> +          printf ("error: pthread_join: %m\n");
> +          errors = true;
> +          return;
> +        }
> +    };
> +  std::function<void (void *(void *))> do_std_thread =
> +    [](void *(func) (void *))
> +    {
> +      std::thread thr{[func] {func (nullptr);}};
> +      thr.join ();
> +    };
> +
> +  std::array<std::pair<const char *, std::function<void (void *(void *))>>, 2>
> +    do_thread_X
> +      {{
> +        {"pthread_create", do_pthread},
> +        {"std::thread", do_std_thread},
> +      }};
> +
> +  for (auto do_thread : do_thread_X)
> +    {
> +      printf ("info: testing %s\n", do_thread.first);
> +      check_counters ("initial", "0/0 0/0 0/0 0/0");
> +      do_thread.second (thread_without_access);
> +      check_counters ("after thread_without_access", "0/0 0/0 0/0 0/0");
> +      reset_all ();
> +      do_thread.second (thread_with_access);
> +      check_counters ("after thread_with_access", "1/1 1/1 1/1 1/1");
> +      reset_all ();
> +    }
> +
> +  return errors;
> +}
> +
> +#define TEST_FUNCTION do_test ()
> +#include "../test-skeleton.c"
>