g++ problem with classes and __attribute__(section)

[Christopher Faylor <cgf at redhat dot com>]

I think the code below illustrates a problem with g++ and the use
of __attribute__((section("whatever"))) .

As you can see from the assembly language below, there seems to
be two variables occupying the same space.  I notice this in cygwin
where the section attribute is used to control what data elements
get copied in a fork.

FWIW, if I remove the section attribute things seem to work ok.
Things also seem to work ok if I comment out the constructor.

This problem is evidenced in a linux x cygwin g++ built from cvs a
couple of minutes ago.

cgf

#include <stdlib.h>
class foo
{
  int bar;
public:
  foo() : bar(37) {}
  int val() {return bar;}
};

int main ()
{
  static foo __attribute__((section(".data42"))) blah;
  static foo __attribute__((section(".data42"))) blah1;
  exit(blah.val () + blah1.val ());
}

	.file	"tst.cc"
.lcomm __ZGVZ4mainE4blah,16
.lcomm __ZGVZ4mainE5blah1,16
	.def	___main;	.scl	2;	.type	32;	.endef
	.section	.data42,"w"
	.align 4
_ZZ4mainE4blah:
	.align 4	# note lack of any directive to set aside space
_ZZ4mainE5blah1:	# should be one after this, too
	.text
	.align 2
	.p2align 4,,15
.globl _main
	.def	_main;	.scl	2;	.type	32;	.endef
_main:
	pushl	%ebp
	movl	%esp, %ebp
	subl	$8, %esp
	xorl	%eax, %eax
	andl	$-16, %esp
	call	__alloca
	call	___main
	cmpb	$0, __ZGVZ4mainE4blah
	jne	L2
	movb	$1, __ZGVZ4mainE4blah
	movl	$37, %eax
	movl	%eax, _ZZ4mainE4blah
L2:
	cmpb	$0, __ZGVZ4mainE5blah1
	jne	L4
	movb	$1, __ZGVZ4mainE5blah1
	movl	$37, %ecx
	movl	%ecx, _ZZ4mainE5blah1
L4:
	movl	_ZZ4mainE5blah1, %eax
	movl	_ZZ4mainE4blah, %edx
	addl	%edx, %eax
	movl	%eax, (%esp)
	call	_exit
	.def	_exit;	.scl	3;	.type	32;	.endef