Re: libstdc++/8231: iostream header position causes bad code generation

Re: libstdc++/8231: iostream header position causes bad code generation

[paolo]

Synopsis: iostream header position causes bad code generation

Responsible-Changed-From-To: unassigned->ljrittle
Responsible-Changed-By: paolo
Responsible-Changed-When: Sat Nov  2 13:43:29 2002
Responsible-Changed-Why:
    Loren, could you please have a look at this PR, which, if
    still an issue with current mainline and 3_2, seems
    definitely target specific?
    Thanks, Paolo.
State-Changed-From-To: feedback->analyzed
State-Changed-By: paolo
State-Changed-When: Sat Nov  2 13:43:29 2002
State-Changed-Why:
    Of course my first tests on i686-pc-linux-gnu from
    freebsd4.6 preprocessed source are completely meaningless
    :-( Sorry.
    
    Anyway, this is the source I have:
     
    // ----------------------------------
    
    //#include <iostream>  // *1*
    
    class A
    {
      public:
        A(const char *addr);
        std::ostream &print(std::ostream &ostr) const;
    
      private:
        long address;
    };
    
    //#include <iostream>  // *2*
    
    std::ostream &operator<<(std::ostream &ostr, const A &addr)
    {
      return addr.print(ostr);
    }
    
    //#include <iostream>  // *3*
    
    std::ostream &A::print(std::ostream &ostr) const
    {
      return ostr << "OK";
    }
    
    //#include <iostream>  // *4*
    
    A::A(const char *)
    {
      address = 0xa000001;
    }
    
    //#include <iostream>   // *5*
    
    int main(int argc, char **argv)
    {
      A a1("x");
      std::cout << "result: " << a1 << std::endl;
    }
    
    // -------------------------------------
    
    With current mainline and 3_2-branch on i686-pc-linux-gnu
    only including in // *1* leads to a succesfull compilation.
    In that case the run-time behaviour is Ok.
    
    paolo:~/Gcc/PRs/v3/Analyzed> a.out
    result: OK

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8231

Re: libstdc++/8231: iostream header position causes bad code generation

[ljrittle]

Synopsis: iostream header position causes bad code generation

State-Changed-From-To: analyzed->closed
State-Changed-By: ljrittle
State-Changed-When: Mon Nov  4 14:32:21 2002
State-Changed-Why:
    Paolo,
    if the include of <iostream> is not in position #1, then
    
        #include <iosfwd>
    
    must appear there, no?
    
    It is not legal to move the include of <iostream> out of
    position #1 in any other case.  In any event, with your
    example, it is not OK to move the include of <iostream>
    past position #3.  Doing so is lying to the compiler.
    As TC++PL-SE says it, <iosfwd> is sufficient to refer
    to all things declared in <iostream> but not to apply
    operations to them.
    
    Not a regression but rather a more agressive use of the properties of the standard (in case this worked with libstdc++-v2).

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8231

Re: libstdc++/8231: iostream header position causes bad code generation

[brister]

The following reply was made to PR libstdc++/8231; it has been noted by GNATS.

From: brister@nominum.com
To: paolo@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
	nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: libstdc++/8231: iostream header position causes bad code generation
Date: Sat, 2 Nov 2002 22:06:20 +0100

 I'm sorry, but I don't have the original any more. It was under rapid change
 so I merged the files together and made it as simple as possible to show the
 bug.
 
 > Synopsis: iostream header position causes bad code generation
 > State-Changed-From-To: open->feedback
 > State-Changed-By: paolo
 > State-Changed-When: Sat Nov  2 12:48:37 2002
 > State-Changed-Why:
 >     I can reproduce the problem on i686-pc-linux-gnu from
 >     your preprocessed file.
 >     However, could you possibly provide also the plain source
 >     and describe the problem referring to specific line
 >     numbers of it? This would speed-up the processing of the PR.
 >     Thanks, Paolo.
 
 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8231
 
 -- 
 James Brister                                            brister@nominum.com
 Nominum Inc.

Re: libstdc++/8231: iostream header position causes bad code generation

[paolo]

Synopsis: iostream header position causes bad code generation

State-Changed-From-To: open->feedback
State-Changed-By: paolo
State-Changed-When: Sat Nov  2 12:48:37 2002
State-Changed-Why:
    I can reproduce the problem on i686-pc-linux-gnu from
    your preprocessed file.
    However, could you possibly provide also the plain source
    and describe the problem referring to specific line
    numbers of it? This would speed-up the processing of the PR.
    Thanks, Paolo.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8231