RE: optimization/3329: optimization large memory copies uses kern el memcpy function without user's knowledge.

["Araneda, Dorian" <dorian dot araneda at intel dot com>]

The following reply was made to PR optimization/3329; it has been noted by GNATS.

From: "Araneda, Dorian" <dorian.araneda@intel.com>
To: "'Richard Henderson'" <rth@redhat.com>
Cc: "'Andrew Pinski'" <pinskia@physics.uc.edu>,
   "'rth@gcc.gnu.org'"<rth@gcc.gnu.org>,
   "'gcc-bugs@gcc.gnu.org'" <gcc-bugs@gcc.gnu.org>,
   "'gcc-prs@gcc.gnu.org'" <gcc-prs@gcc.gnu.org>,
   "'nobody@gcc.gnu.org'"<nobody@gcc.gnu.org>,
   "'gcc-gnats@gcc.gnu.org'" <gcc-gnats@gcc.gnu.org>
Subject: RE: optimization/3329: optimization large memory copies uses kern
	 el memcpy function without user's knowledge.
Date: Tue, 2 Apr 2002 14:29:35 -0800 

 this may be the case, but I don't think 
 a developer should know the kernel-hacking tricks 
 to get their code to be portable across kernels.
 
 x=y; 
 is not intuitively interpreted as 
 memcpy(&x,y,sizeof(x));
 
 I can assure you that if gcc did a survey of all
 the developers using gcc, the vast majority
 would not have realized this was occurring
 in their code.
 
 if this is not the case and I am a twink when 
 it comes to kernel development, gcc should still
 be idiot proof. the compiler  should not make
 assumptions that the user is ok with linking
 unapproved kernel function calls.
 
 is simple, I don't appreciate a compiler feature
 that goes behind my back to include code I did not
 ask for.
 
 It is like someone who thinks they are being
 polite by pushing someone in a wheelchair because
 they feel that they need the help.
 It is not good etiquette to do that when that
 person neither asked for help or gave permission
 to be pushed.
  
 gcc may have had good intentions but is still
 not right to override the user's intent in that
 way.
 
 I do not see why it is so hard to understand
 what I am trying to explain.  It is not about
 what method is better.  It's about common courtesy
 to the user.
 
 -Dorian
 
 -----Original Message-----
 From: Richard Henderson [mailto:rth@redhat.com]
 Sent: Tuesday, April 02, 2002 5:02 PM
 To: Araneda, Dorian
 Cc: 'Andrew Pinski'; 'rth@gcc.gnu.org'; 'gcc-bugs@gcc.gnu.org';
 'gcc-prs@gcc.gnu.org'; 'nobody@gcc.gnu.org'; 'gcc-gnats@gcc.gnu.org'
 Subject: Re: optimization/3329: optimization large memory copies uses
 kern el memcpy function without user's knowledge.
 
 
 There are two markups that export symbols from the kernel:
 
  (1) EXPORT_SYMBOL
 
 	This is used for symbols with which there are no
 	restrictions for use.
 
  (2) EXPORT_SYMBOL_GPL
 
 	This is used for symbols that may only be used with
 	modules that carry a GPL compatible license.
 
 See linux/Documentation/DocBook/kernel-hacking.tmpl or
 some post-processing thereof.
 
 You will find that memcpy and all of the other gcc support
 routines are exported with EXPORT_SYMBOL, and thus do not
 contaminate your code.
 
 
 r~