Re: Wrong g++ output (egcs-1.1.[12])

["Martin v. Loewis" <martin at mira dot isdn dot cs dot tu-berlin dot de>]

> The compiler doesn't complain.  But when I look at the assembly output,
> I can see that it calls the wrong destructors.

Thanks again for your report. Based on your information, I have
reproduced the problem in the example below. When compiled with
egcs-2.91.60 on i586-pc-linux-gnu, this code prints

Foo::Foo

This is wrong, it should call 'Bar::Bar'. With the development
snapshot, it works correctly.

The problem is that egcs makes the constructors of the anonymous
unions weak, so during linking, the right copy is eliminated. I
believe this was fixed with

1998-08-20  Jason Merrill  <jason@yorick.cygnus.com>

	(grokfndecl): Likewise.  Members of anonymous types have no linkage.

In this specific example, a different fix would be to use 'the typedef
name for linkage purposes'. Then, the constructors do not need to be
duplicated in different translation units.

Jakob, as a work-around, you should give the types explicit names,
like

typedef struct D { int foobar; } D;

This will avoid the problem.

Hope this helps,
Martin

#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.2).
# To extract the files from this archive, save it to some FILE, remove
# everything before the `!/bin/sh' line above, then type `sh FILE'.
#
# Made on 1999-03-27 21:57 CET by <martin@mira>.
# Source directory was `/home/martin/tmp'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode       name
# ------ ---------- ------------------------------------------
#     64 -rw-rw-r-- makefile
#     59 -rw-rw-r-- x1.cc
#    216 -rw-rw-r-- x2.cc
#     57 -rw-rw-r-- x1.h
#
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=FAILED
locale_dir=FAILED
first_param="$1"
for dir in $PATH
do
  if test "$gettext_dir" = FAILED && test -f $dir/gettext \
     && ($dir/gettext --version >/dev/null 2>&1)
  then
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    if test "$3" = GNU
    then
      gettext_dir=$dir
    fi
  fi
  if test "$locale_dir" = FAILED && test -f $dir/shar \
     && ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
  then
    locale_dir=`$dir/shar --print-text-domain-dir`
  fi
done
IFS="$save_IFS"
if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
then
  echo=echo
else
  TEXTDOMAINDIR=$locale_dir
  export TEXTDOMAINDIR
  TEXTDOMAIN=sharutils
  export TEXTDOMAIN
  echo="$gettext_dir/gettext -s"
fi
touch -am 1231235999 $$.touch >/dev/null 2>&1
if test ! -f 1231235999 && test -f $$.touch; then
  shar_touch=touch
else
  shar_touch=:
  echo
  $echo 'WARNING: not restoring timestamps.  Consider getting and'
  $echo "installing GNU \`touch', distributed in GNU File Utilities..."
  echo
fi
rm -f 1231235999 $$.touch
#
if mkdir _sh13179; then
  $echo 'x -' 'creating lock directory'
else
  $echo 'failed to create lock directory'
  exit 1
fi
# ============= makefile ==============
if test -f 'makefile' && test "$first_param" != -c; then
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else
  $echo 'x -' extracting 'makefile' '(text)'
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x:	x1.o  x2.o
X	$(CXX)	-o x x2.o x1.o
X
x1.o:	x1.cc
X
x2.o:	x2.cc
X
SHAR_EOF
  $shar_touch -am 0327215699 'makefile' &&
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fi
# ============= x1.cc ==============
if test -f 'x1.cc' && test "$first_param" != -c; then
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else
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struct {int i;}a1;
struct {int i;}a2;
#include "x1.h"
C c;
SHAR_EOF
  $shar_touch -am 0327214399 'x1.cc' &&
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  $echo 'restore of' 'x1.cc' 'failed'
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a93697abe4d2f1b8f8023db03216b7f3  x1.cc
SHAR_EOF
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fi
# ============= x2.cc ==============
if test -f 'x2.cc' && test "$first_param" != -c; then
  $echo 'x -' SKIPPING 'x2.cc' '(file already exists)'
else
  $echo 'x -' extracting 'x2.cc' '(text)'
  sed 's/^X//' << 'SHAR_EOF' > 'x2.cc' &&
#include <stdio.h>
struct Foo{
X Foo();
};
typedef struct { Foo foobar; } D;
X
#include "x1.h"
X
Foo::Foo()
{
X  printf("Foo::Foo\n");
}
X
Bar::Bar()
{
X  printf("Bar::Bar\n");
}
X
int dummy()
{
X  C c;
X  D d;
}
X
main()
{
}
SHAR_EOF
  $shar_touch -am 0327214599 'x2.cc' &&
  chmod 0664 'x2.cc' ||
  $echo 'restore of' 'x2.cc' 'failed'
  if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
  && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
    md5sum -c << SHAR_EOF >/dev/null 2>&1 \
    || $echo 'x2.cc:' 'MD5 check failed'
37241ef96583e32827a9c319a2777f7d  x2.cc
SHAR_EOF
  else
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    test 216 -eq "$shar_count" ||
    $echo 'x2.cc:' 'original size' '216,' 'current size' "$shar_count!"
  fi
fi
# ============= x1.h ==============
if test -f 'x1.h' && test "$first_param" != -c; then
  $echo 'x -' SKIPPING 'x1.h' '(file already exists)'
else
  $echo 'x -' extracting 'x1.h' '(text)'
  sed 's/^X//' << 'SHAR_EOF' > 'x1.h' &&
struct Bar{
X Bar();
};
typedef struct { Bar foobar; } C;
SHAR_EOF
  $shar_touch -am 0327213299 'x1.h' &&
  chmod 0664 'x1.h' ||
  $echo 'restore of' 'x1.h' 'failed'
  if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
  && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
    md5sum -c << SHAR_EOF >/dev/null 2>&1 \
    || $echo 'x1.h:' 'MD5 check failed'
725d4891c164c66b18aebab0d0e8d570  x1.h
SHAR_EOF
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    test 57 -eq "$shar_count" ||
    $echo 'x1.h:' 'original size' '57,' 'current size' "$shar_count!"
  fi
fi
rm -fr _sh13179
exit 0