C++ PATCH: Problem with local static variable guards with old ABI

[scott snyder <snyder at fnal dot gov>]

hi -

A recent cvs version of gcc (20000703) on an i686-pc-linux platform
screws up the guards for local static variables when the old ABI is
being used.

Here's an example:

-- x1.cc --------------------------------------------------------------
extern "C" void puts (const char*);

struct S
{
  S () { puts ("S ctor"); }
};

void foo ()
{
  puts ("foo");
  static S s;
}

extern void bar ();

int main ()
{
  foo ();
  bar ();
  return 0;
}
-- x2.cc --------------------------------------------------------------
extern "C" void puts (const char*);

struct S
{
  S () { puts ("S ctor"); }
};

void bar ()
{
  puts ("bar");
  static S s;
}

-----------------------------------------------------------------------

Compile these two and link them together:

$ g++ -o x x1.cc x2.cc
$ ./x
foo
S ctor
bar

Note the S constructor is called only once, even though two objects
are created.

Here are the relevant excerpts from the assembly output for x1.cc:

gcc2_compiled.:
	.local	s.0
	.comm	s.0,1,1
	.local	_.tmp_0.1
	.comm	_.tmp_0.1,4,4
	.comm	__sns.0,4,4

...

foo__Fv:

	cmpl	$0, __sns.0
	jne	.L4
	subl	$12, %esp
	pushl	$s.0
	call	__1S
	addl	$16, %esp
	movl	%eax, -4(%ebp)
	movl	$1, __sns.0
.L4:


Here, the symbol __sns.0 is being used as the guard.  However,
it is not declared .local --- so one instance of the guard gets
shared between the two compilation units!

I think this is the fix:

2000-07-04  scott snyder  <snyder@fnal.gov>

	* decl2.c (get_guard): Add missing return for old ABI local
	variable case.

Index: decl2.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/cp/decl2.c,v
retrieving revision 1.375
diff -u -p -c -p -r1.375 decl2.c
*** decl2.c	2000/07/03 15:43:49	1.375
--- decl2.c	2000/07/04 06:35:09
*************** get_guard (decl)
*** 2874,2879 ****
--- 2874,2880 ----
      {
        guard = get_temp_name (integer_type_node);
        rest_of_decl_compilation (guard, NULL_PTR, 0, 0);
+       return guard;
      }
  
    if (!flag_new_abi)