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* Re: c++/2948
@ 2001-05-30 13:16 Sean McNeil
  0 siblings, 0 replies; 2+ messages in thread
From: Sean McNeil @ 2001-05-30 13:16 UTC (permalink / raw)
  To: nobody; +Cc: gcc-prs

The following reply was made to PR c++/2948; it has been noted by GNATS.

From: Sean McNeil <sean@mcneil.com>
To: neil@gcc.gnu.org
Cc: gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org
Subject: Re: c++/2948
Date: Wed, 30 May 2001 13:12:54 -0700

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 I have found the following information in cp/decl.c:
 
   /* In a virtual destructor, we must call delete.  */
   if (DECL_VIRTUAL_P (current_function_decl))
     {
       tree if_stmt;
       tree virtual_size = c_sizeof (current_class_type);
 
       /* [class.dtor]
 
   At the point of definition of a virtual destructor (including
   an implicit definition), non-placement operator delete shall
   be looked up in the scope of the destructor's class and if
   found shall be accessible and unambiguous.  */
       exprstmt = build_op_delete_call
  (DELETE_EXPR, current_class_ptr, virtual_size,
   LOOKUP_NORMAL | LOOKUP_SPECULATIVELY, NULL_TREE);
 
       if_stmt = begin_if_stmt ();
       finish_if_stmt_cond (build (BIT_AND_EXPR, integer_type_node,
       current_in_charge_parm,
       integer_one_node),
       if_stmt);
       finish_expr_stmt (exprstmt);
       finish_then_clause (if_stmt);
       finish_if_stmt ();
     }
 
 which accounts for the undefined reference to the "operator delete
 (void*)" I am seeing.  Now... why would a virtual destructor require a
 call to the delete operator would be nice to know, yet why this behaves
 differently under the different scenarios is a bigger puzzle to me.  The
 differences I've seen with the #pragma implementation are documented as
 relating to templates, not virtual destructors.
 
 I have verified the introduction on the undefined reference is from the
 above code by commenting it out.
 
 Sean
 
 neil@gcc.gnu.org wrote:
 
 > Synopsis: different behaviour directly to C++ vs. saving -E output
 >
 > State-Changed-From-To: feedback->analyzed
 > State-Changed-By: neil
 > State-Changed-When: Tue May 29 10:30:40 2001
 > State-Changed-Why:
 >     Appears to be a C++ front-end bug in interpreting filenames
 >     passed from CPP when handling #pragma implementation.
 >
 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=2948&database=gcc
 
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 <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
 <html>
 I have found the following information in cp/decl.c:
 <p>&nbsp; /* In a virtual destructor, we must call delete.&nbsp; */
 <br>&nbsp; if (DECL_VIRTUAL_P (current_function_decl))
 <br>&nbsp;&nbsp;&nbsp; {
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tree if_stmt;
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tree virtual_size = c_sizeof (current_class_type);
 <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /* [class.dtor]
 <p>&nbsp; At the point of definition of a virtual destructor (including
 <br>&nbsp; an implicit definition), non-placement operator delete shall
 <br>&nbsp; be looked up in the scope of the destructor's class and if
 <br>&nbsp; found shall be accessible and unambiguous.&nbsp; */
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; exprstmt = build_op_delete_call
 <br>&nbsp;(DELETE_EXPR, current_class_ptr, virtual_size,
 <br>&nbsp; LOOKUP_NORMAL | LOOKUP_SPECULATIVELY, NULL_TREE);
 <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if_stmt = begin_if_stmt ();
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; finish_if_stmt_cond (build (BIT_AND_EXPR,
 integer_type_node,
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; current_in_charge_parm,
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; integer_one_node),
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if_stmt);
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; finish_expr_stmt (exprstmt);
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; finish_then_clause (if_stmt);
 <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; finish_if_stmt ();
 <br>&nbsp;&nbsp;&nbsp; }
 <p>which accounts for the undefined reference to the "operator delete (void*)"
 I am seeing.&nbsp; Now... why would a virtual destructor require a call
 to the delete operator would be nice to know, yet why this behaves differently
 under the different scenarios is a bigger puzzle to me.&nbsp; The differences
 I've seen with the #pragma implementation are documented as relating to
 templates, not virtual destructors.
 <p>I have verified the introduction on the undefined reference is from
 the above code by commenting it out.
 <p>Sean
 <p>neil@gcc.gnu.org wrote:
 <blockquote TYPE=CITE>Synopsis: different behaviour directly to C++ vs.
 saving -E output
 <p>State-Changed-From-To: feedback->analyzed
 <br>State-Changed-By: neil
 <br>State-Changed-When: Tue May 29 10:30:40 2001
 <br>State-Changed-Why:
 <br>&nbsp;&nbsp;&nbsp; Appears to be a C++ front-end bug in interpreting
 filenames
 <br>&nbsp;&nbsp;&nbsp; passed from CPP when handling #pragma implementation.
 <p><a href=" http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=2948&database=gcc" ;> http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&amp;pr=2948&amp;database=gcc </a></blockquote>
 </html>
 
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^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: c++/2948
@ 2001-05-29 10:36 neil
  0 siblings, 0 replies; 2+ messages in thread
From: neil @ 2001-05-29 10:36 UTC (permalink / raw)
  To: nobody; +Cc: gcc-prs

The following reply was made to PR c++/2948; it has been noted by GNATS.

From: neil@gcc.gnu.org
To: gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org, sean@mcneil.com
Cc:  
Subject: Re: c++/2948
Date: 29 May 2001 17:30:40 -0000

 Synopsis: different behaviour directly to C++ vs. saving -E output
 
 State-Changed-From-To: feedback->analyzed
 State-Changed-By: neil
 State-Changed-When: Tue May 29 10:30:40 2001
 State-Changed-Why:
     Appears to be a C++ front-end bug in interpreting filenames
     passed from CPP when handling #pragma implementation.
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=2948&database=gcc


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2001-05-30 13:16 c++/2948 Sean McNeil
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2001-05-29 10:36 c++/2948 neil

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