[Bug c/40485] New: definitions of __builtin_abs() and abs() function in one module

[Bug c/40485] New: definitions of __builtin_abs() and abs() function in one module

[ivan dot glushkov at gmail dot com]

Hello.

gcc always replaces the name of the defined "__builtin_abs()" with "abs()". And
it might cause the error if we also wants to define "abs()" function:

$ cat t.c
int abs(int a) {return 0;}
int __builtin_abs(int a) {return 0;}
int main(void)
{
    return (abs(-3) + __builtin_abs(-3));
}

$ gcc t.c -c
/tmp/ccdecizd.s: Assembler messages:
/tmp/ccdecizd.s:14: Error: symbol `abs' is already defined



In the case of "static" functions it's OK:

$ cat t.c
static int abs(int a) {return 0;}
static int __builtin_abs(int a) {return 0;}
int main(void)
{
    return (abs(-3) + __builtin_abs(-3));
}

$ gcc t.c -c ; echo $?
0

In this case we use unchanged names for the functions' call:

$ gcc t.c -S && grep call t.s
        call    abs
        call    __builtin_abs


This issue doesn't occur only on abs but also with the others builtins.

$ ~/programs/gcc-4.4.0/bin/gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ./configure --prefix=/home/glushkov/programs/gcc-4.4.0
--enable-languages=c,c++
Thread model: posix
gcc version 4.4.0 (GCC)

$ uname -a
Linux expert 2.6.23-gentoo-r9-c2-uni1 #1 SMP Thu Jun 5 13:00:21 MSD 2008 i686
Intel(R) Pentium(R) 4 CPU 3.40GHz GenuineIntel GNU/Linux


-- 
           Summary: definitions of __builtin_abs() and abs() function in one
                    module
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ivan dot glushkov at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-06-18 09:35 -------
This is really invalid code, but we should diagnose it.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |accepts-invalid
   Last reconfirmed|0000-00-00 00:00:00         |2009-06-18 09:35:53
               date|                            |
            Summary|definitions of              |definitions of
                   |__builtin_abs() and abs()   |__builtin_abs() and abs()
                   |function in one module      |function in one module not
                   |                            |diagnosed
            Version|unknown                     |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[ivan dot glushkov at gmail dot com]

------- Comment #2 from ivan dot glushkov at gmail dot com  2009-06-18 09:48 -------
Why invalid? And why non-static is not invalid?
Can you please give me reference to documentation where it's described?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2009-06-18 13:48 -------
The __builtin_ namespace is reserved by GCC.  There may be documentation
missing for this fact.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2009-06-18 14:51 -------
All of __* namespace s reserved for the implementor.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[joseph at codesourcery dot com]

------- Comment #5 from joseph at codesourcery dot com  2009-06-18 21:08 -------
Subject: Re:  definitions of __builtin_abs() and abs() function
 in one module not diagnosed

What happened to the patch for PR 32455 to disallow __builtin_* 
declarations?  That PR indicates it was approved for 4.5.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485

[Bug c/40485] definitions of __builtin_abs() and abs() function in one module not diagnosed

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2009-06-21 22:45 -------


*** This bug has been marked as a duplicate of 32455 ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40485