tests/exceptions.at

# exception.at -- test C++ exception handling with libtool  -*- Autotest -*-
#
#   Copyright (C) 2010-2019, 2021-2025 Free Software Foundation, Inc.
#
#   This file is part of GNU Libtool.
#
# GNU Libtool is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of
# the License, or (at your option) any later version.
#
# GNU Libtool 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Libtool.  If not, see <https://www.gnu.org/licenses/>.
####

AT_SETUP([C++ exception handling])
AT_KEYWORDS([libtool])
AT_KEYWORDS([libltdl])

: ${LTDLINCL="-I$abs_top_srcdir/libltdl"}
: ${LIBLTDL="$abs_builddir/../libltdl/libltdlc.la"}

# Skip this test when called from:
#    make distcheck DISTCHECK_CONFIGURE_FLAGS=--disable-ltdl-install
AT_CHECK([case $LIBLTDL in #(
 */_inst/lib/*) test -f "$LIBLTDL" || (exit 77) ;;
esac], [], [ignore])

CPPFLAGS="$LTDLINCL $CPPFLAGS"

# Win32 (and cygwin) notes
# ------------------------
# When using C++ and Win32 DLLs, data types used in the DLL's interface
# that are other-than-POD, must have vtables, typeinfo, and other
# elements resolved when the client is linked.  This includes exception
# classes.  Therefore, the exception class "modexc" thrown by the
# dynamically-loaded module must be defined in a separate DLL, to which
# both that module and main must be directly linked; hence, the 'common'
# library. Not using a 'common' library in this manner represents an
# ODR violation, unless the platform's runtime loader is capable of
# rationalizing vague linkage items such as vtables, typeinfo, and
# typename elements) at runtime.  The Win32 loader is not capable of
# this, but some ELF loaders appear to be.
#
# Similar treatment is not necessary for liba (e.g. the libexc
# exception class), because that library is not dynamically loaded. As a
# consequence, vague linkage items for the class libexc are resolved at
# link time using the vague linkage rules, for both Win32 and other
# (e.g. ELF) platforms.
#
# Also, when linking a C++ DLL with another C++ DLL, some versions of
# the GNU toolchain on Win32 (or cygwin) mistakenly re-export symbols
# that were imported from the other DLL, when the client DLL is linked
# using -export-all-symbols.  Similar issues MAY also arise with those
# versions of the GNU toolchain if using the libtool link flags
# -export-symbols LIST or -export-symbols-regex REGEX, if any symbols
# from the dependency, rather than client, library are listed (or match
# the regex).  However, in this test, none of these situations apply,
# so we don't directly address it.  Otherwise, the correct mechanism
# would be to avoid all of those flags, and instead explicitly decorate
# all symbols with appropriate __declspec (dllexport) or
# __declspec (dllimport) flags when building the DLLs and the clients.
#
# For more information, see these two threads:
#   http://lists.gnu.org/archive/html/bug-libtool/2010-06/msg00069.html
#   http://cygwin.com/ml/cygwin/2010-06/msg00392.html
# To sum up: C++ is complicated.
AT_DATA([common.h],
[[#ifndef LIBTOOL_TEST_COMMON_HEADER
#define LIBTOOL_TEST_COMMON_HEADER

#include <exception>
#include <string>

#if defined __CYGWIN__ || defined _WIN32
# if defined DLL_EXPORT || defined USING_COMMON_DLL
#  if defined LIBTOOL_TEST_IN_COMMON
#   define COMMON_IMPEXP __declspec (dllexport)
#  else
#   define COMMON_IMPEXP __declspec (dllimport)
#  endif
# else
#  define COMMON_IMPEXP
# endif
#else
# define COMMON_IMPEXP
#endif

#if __cplusplus >= 201103L
# define ATTRIBUTE_THROW(type) noexcept (false)
# define ATTRIBUTE_NOTHROW noexcept (true)
#else
# define ATTRIBUTE_THROW(type) throw (type)
# define ATTRIBUTE_NOTHROW throw ()
#endif

class COMMON_IMPEXP modexc : public std::exception {
public:
  modexc (std::string str) : message (str) { }
  ~modexc () ATTRIBUTE_NOTHROW { }
  virtual const char *what () const ATTRIBUTE_NOTHROW
  {
    return message.c_str ();
  }
private:
  std::string message;
};

extern "C" int COMMON_IMPEXP common_dummy (void);
#endif
]])

AT_DATA([common.cpp],
[[#define LIBTOOL_TEST_IN_COMMON
#include "common.h"

extern "C"
int common_dummy (void)
{
  return 0;
}
]])

AT_DATA([module.h],
[[#include "common.h"

#if defined __CYGWIN__ || defined _WIN32
# if defined DLL_EXPORT || defined USING_MODULE_DLL
#  if defined LIBTOOL_TEST_IN_MODULE
#   define MODULE_IMPEXP __declspec (dllexport)
#  else
#   define MODULE_IMPEXP __declspec (dllimport)
#  endif
# else
#  define MODULE_IMPEXP
# endif
#else
# define MODULE_IMPEXP
#endif

extern "C" int MODULE_IMPEXP modfoo () ATTRIBUTE_THROW (modexc);
]])

AT_DATA([module.cpp],
[[#include <iostream>
#define LIBTOOL_TEST_IN_MODULE
#include "module.h"

int modbar (void) ATTRIBUTE_THROW (modexc)
{
  throw modexc ("exception in module");
}

extern "C"
int modfoo (void) ATTRIBUTE_THROW (modexc)
{
  try {
    modbar ();
  }
  catch (modexc e) {
    std::cerr << "caught inside module: " << e.what () << '\n';
    throw modexc ("exception from module");
  }
  return 0;
}
]])

AT_DATA([lib.h],
[[#include <exception>
#include <string>


#if defined __CYGWIN__ || defined _WIN32
# if defined DLL_EXPORT || defined USING_LIB_DLL
#  if defined LIBTOOL_TEST_IN_LIB
#   define LIB_IMPEXP __declspec (dllexport)
#  else
#   define LIB_IMPEXP __declspec (dllimport)
#  endif
# else
#  define LIB_IMPEXP
# endif
#else
# define LIB_IMPEXP
#endif

#if __cplusplus >= 201103L
# define ATTRIBUTE_THROW(type) noexcept (false)
# define ATTRIBUTE_NOTHROW noexcept (true)
#else
# define ATTRIBUTE_THROW(type) throw (type)
# define ATTRIBUTE_NOTHROW throw ()
#endif

class LIB_IMPEXP libexc : public std::exception {
public:
  libexc (std::string str) : message (str) { }
  ~libexc () ATTRIBUTE_NOTHROW { }
  virtual const char *what () const ATTRIBUTE_NOTHROW
  {
    return message.c_str ();
  }
private:
  std::string message;
};
int LIB_IMPEXP libfoo () ATTRIBUTE_THROW (libexc);
]])

AT_DATA([lib.cpp],
[[#include <iostream>
#define LIBTOOL_TEST_IN_LIB
#include "lib.h"

int libbar (void) ATTRIBUTE_THROW (libexc)
{
  throw libexc ("exception in library");
}

int libfoo (void) ATTRIBUTE_THROW (libexc)
{
  try {
    libbar ();
  }
  catch (libexc e) {
    std::cerr << "caught inside lib: " << e.what () << '\n';
    throw libexc ("exception from library");
  }
  return 0;
}
]])

AT_DATA([main.cpp],
[[#include <ltdl.h>
#include <cstdlib>
#include <iostream>
#include <exception>
#include <string>
#include "common.h"
#include "lib.h"
#include "module.h"

class exc : public std::exception {
public:
  exc (std::string str) : message (str) { }
  ~exc () ATTRIBUTE_NOTHROW { }
  virtual const char *what () const ATTRIBUTE_NOTHROW
  {
    return message.c_str ();
  }
private:
  std::string message;
};

int foo (void) ATTRIBUTE_THROW (exc)
{
  throw exc ("exception in program");
  return 0;
}

int exceptions_in_prog (void)
{
  std::cerr << "exceptions_in_prog\n";
  try {
    foo ();
  }
  catch (exc e) {
     std::cerr << "caught: " << e.what () << '\n';
    return 0;
  }
  return 1;
}

int exceptions_in_lib (void)
{
  std::cerr << "exceptions_in_lib\n";
  try {
    libfoo ();
  }
  catch (libexc e) {
     std::cerr << "caught: " << e.what () << '\n';
    return 0;
  }
  return 1;
}

int exceptions_in_module (void)
{
  std::cerr << "exceptions_in_module\n";

  if (lt_dlinit ())
    {
      std::cerr << "init error: " << lt_dlerror () << '\n';
      return 1;
    }

  // Some systems need RTLD_GLOBAL for exceptions to work in modules.
  lt_dladvise advise;
  if (lt_dladvise_init (&advise) || lt_dladvise_global (&advise))
    {
      std::cerr << "error setting advise global\n";
      return 1;
    }

  lt_dlhandle handle = lt_dlopenadvise ("module.la", advise);
  if (handle == NULL)
    {
      std::cerr << "dlopen failed: " << lt_dlerror () << '\n';
      return 1;
    }
  lt_dladvise_destroy (&advise);

  typedef int (*pfun) (void);
  pfun pf = (pfun) lt_dlsym (handle, "modfoo");
  if (pf == NULL)
    {
      std::cerr << "dlsym failed: " << lt_dlerror () << '\n';
      return 1;
    }

  bool exception_caught = false;
  try {
    (*pf) ();
  }
  catch (modexc e) {
    std::cerr << "caught: " << e.what () << '\n';
    exception_caught = true;
  }

  /* Only close the module after all of its objects have gone out of scope. */
  if (exception_caught)
  {
    if (lt_dlclose (handle))
      {
        std::cerr << "dlclose failed: " << lt_dlerror () << '\n';
	return 1;
      }
    if (lt_dlexit ())
      {
        std::cerr << "lt_dlexit failed: " << lt_dlerror () << '\n';
	return 1;
      }
    return 0;
  }
  return 1;
}

int main (void)
{

  LTDL_SET_PRELOADED_SYMBOLS();

  if (exceptions_in_prog ())
    return 1;
  if (exceptions_in_lib ())
    return 1;
  if (exceptions_in_module ())
    return 1;
  return 0;
}
]])

inst=`pwd`/inst
libdir=$inst/lib
bindir=$inst/bin
moddir=$inst/mod
mkdir l m $inst $libdir $bindir $moddir

# If the C++ compiler isn't capable, don't bother.
AT_CHECK([$CXX $CPPFLAGS $CXXFLAGS -DUSING_COMMON_DLL -DUSING_MODULE_DLL -DUSING_LIB_DLL -c main.cpp || exit 77], [], [ignore], [ignore])

AT_CHECK([$LIBTOOL --mode=compile --tag=CXX $CXX $CPPFLAGS $CXXFLAGS -c common.cpp],
	   [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=compile --tag=CXX $CXX $CPPFLAGS $CXXFLAGS -c lib.cpp],
	   [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=compile --tag=CXX $CXX $CPPFLAGS $CXXFLAGS -DUSING_COMMON_DLL -c module.cpp],
	   [], [ignore], [ignore])

AT_CHECK([$LIBTOOL --mode=link --tag=CXX $CXX $CXXFLAGS $LDFLAGS -o l/libcommon.la ]dnl
	 [common.lo -no-undefined -version-info 1:0:0 -rpath $libdir],
	 [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=link --tag=CXX $CXX $CXXFLAGS $LDFLAGS -o l/liba.la ]dnl
	 [lib.lo -no-undefined -version-info 1:0:0 -rpath $libdir],
	 [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=link --tag=CXX $CXX $CXXFLAGS $LDFLAGS -o m/module.la ]dnl
	 [module.lo l/libcommon.la -module -avoid-version -no-undefined -rpath $moddir],
	 [], [ignore], [ignore])

# We need -export-dynamic for the exception handling in modules to work.
AT_CHECK([$LIBTOOL --mode=link --tag=CXX $CXX $CXXFLAGS $LDFLAGS -o main$EXEEXT ]dnl
	 [main.$OBJEXT l/liba.la l/libcommon.la -dlopen m/module.la $LIBLTDL -export-dynamic],
	 [], [ignore], [ignore])

LT_AT_NOINST_EXEC_CHECK([./main], [-dlopen m/module.la], [], [ignore], [ignore])

AT_CHECK([$LIBTOOL --mode=install cp l/libcommon.la $libdir],
	 [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=install cp l/liba.la $libdir],
	 [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=install cp m/module.la $moddir],
	 [], [ignore], [ignore])
AT_CHECK([$LIBTOOL --mode=install cp main$EXEEXT $bindir],
	 [], [ignore], [ignore])
rm -rf l m main$EXEEXT

LTDL_LIBRARY_PATH=$moddir
export LTDL_LIBRARY_PATH
LT_AT_EXEC_CHECK([$bindir/main], [], [ignore], [ignore])

AT_CLEANUP