[Bug preprocessor/21250] New: line number 0 for <built-in> causes GAS to complain

[Bug preprocessor/21250] New: line number 0 for <built-in> causes GAS to complain

[segher at kernel dot crashing dot org]

powerpc64-linux-gcc -c -o any-file.o any-file.S 
 
results in 
 
any-file.S: Assembler messages: 
any-file.S:1: Warning: line numbers must be positive; line number 0 rejected 
 
as the pre-processed file looks like 
 
# 1 "any-file.S" 
# 0 "<built-in>" 
# 1 "<command line>" 
# 1 "any-file.S" 
... 
 
This regression is caused by 
 
http://gcc.gnu.org/ml/gcc-patches/2005-04/msg02132.html

-- 
           Summary: line number 0 for <built-in> causes GAS to complain
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: segher at kernel dot crashing dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc-linux
  GCC host triplet: powerpc-linux
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] line number 0 for <built-in> causes GAS to complain

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bothner at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|line number 0 for <built-in>|[4.1 Regression] line number
                   |causes GAS to complain      |0 for <built-in> causes GAS
                   |                            |to complain
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[bothner at gcc dot gnu dot org]

------- Additional Comments From bothner at gcc dot gnu dot org  2005-04-28 05:12 -------
Not sure what the right solution is.
We should be consistent as to whether definitions in <built-in>
have line 0 and line 1, and it wasn't before my change.
One option is to fix gas.
Another if to suppress the # 0 <built-in> line, as it doesn't
seem very useful.
Another is to declare this a gas bug.
There are of course others ....
(However, I'm on vacation and away from home, so deeling
with email and bugs i difficult.)

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |bothner at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-04-28 05:12:41
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[segher at kernel dot crashing dot org]

------- Additional Comments From segher at kernel dot crashing dot org  2005-04-28 15:08 -------
The C standard has this to say about line numbers, in 6.10.4/2:

The line number of the current source line is one greater than the number of new-line characters read 
or introduced in translation phase 1 (5.1.1.2) while processing the source file to the current token. 

So, a line number of 0 is impossible.  GAS is correct to complain about this.

It would be nice to be consistent, yes; but consistently right, please, not
consistently wrong ;-)

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[bothner at gcc dot gnu dot org]

------- Additional Comments From bothner at gcc dot gnu dot org  2005-04-28 23:59 -------
Re comment #2:

I don't believe the text you quoted from the C standard is relevant.
<built-in> is not a "source file".

While the C standard isn't directly relevant to Gas, a relevant issue
is what the C standard says of #line directives: Should a C compiler
complain if it sees a line number zero in a #line directive?  Note this
is directly answered by your quotation.

But rather than argue standards, my inclination would be to use zero
as the pseudo-line-number of <built-in> declarations, but suppress the
output of the # 0 <built-in> in preprocessor output.  This will have to
be discussed on the gcc/gcc-patches mailing list (after I get back home).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-17 21:55 -------
*** Bug 21634 has been marked as a duplicate of this bug. ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |falk at debian dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250

[Bug preprocessor/21250] [4.1 Regression] line number 0 for <built-in> causes GAS to complain

[ppluzhnikov at charter dot net]

------- Additional Comments From ppluzhnikov at charter dot net  2005-09-15 23:31 -------
The line '#0 <built-in>' causes trouble for other tools that work with 
the output from 'gcc -E'; e.g. edgcpfe refuses to parse it:

$ gcc -E - < /dev/null > junk.i && edgcpfe --c junk.i
"<stdin>", line 1: error: invalid line number
  # 0 "<built-in>"
    ^

1 error detected in the compilation of "junk.i".

What is the problem of emitting '#1 <built-in>' anyway?
Since neither corresponds to a "real" line number, it's not clear what
advantage '#0' has, especially if it is to be suppressed in the output.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ppluzhnikov at charter dot
                   |                            |net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21250