[Bug preprocessor/51745] New: Strange symbol appears when using commandline definition without "="

[Bug preprocessor/51745] New: Strange symbol appears when using commandline definition without "="

[mikulas at artax dot karlin.mff.cuni.cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51745

             Bug #: 51745
           Summary: Strange symbol appears when using commandline
                    definition without "="
    Classification: Unclassified
           Product: gcc
           Version: 4.6.2
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikulas@artax.karlin.mff.cuni.cz
              Host: i686-pc-linux-gnu
            Target: i686-pc-linux-gnu
             Build: i686-pc-linux-gnu


If we use -D definition without "=" in the command line, strange unwanted
symbol "1" appears in the output.

How to reproduce: run gcc -E - -o - "-Dblabla(x, y) bleble[x,y]"
Type blabla(2,3) and press Ctrl-D.
The output is: bleble[2,3] 1
The symbol "1" was never defined anywhere. There is something strange going on
in the commandline parsing. Such syntax without "=" should be either rejected
with an error or it should be processed correctly.

[Bug preprocessor/51745] Strange symbol appears when using commandline definition without "="

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51745

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-01-03 21:48:19 UTC ---
In other words:

$ echo foo | gcc -E - -o - "-Dfoo bar"
# 1 "<stdin>"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "<stdin>"
bar 1

[Bug preprocessor/51745] Strange symbol appears when using commandline definition without "="

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51745

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-04
     Ever Confirmed|0                           |1

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-04 10:21:49 UTC ---
Strangely ICC agrees with GCC here (hopefully using its own preprocessor ;))
So, confirmed, but maybe invalid.

[Bug preprocessor/51745] Strange symbol appears when using commandline definition without "="

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51745

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-04 11:10:07 UTC ---
The 1 comes likely from -Dfoo being equivalent to Dfoo=1 if there is no = on
the command line, and as the preprocessor internally doesn't use = signs but
spaces after macro name, we append " 1". -D"foo bar" is thus expanded as
-D"foo bar 1". "processed correctly" means what exactly?  You can't define
macro blabla(x, y) bleble[x,y], C doesn't have macros with spaces in the names.
 Garbage in garbage out in my eyes.

[Bug preprocessor/51745] Strange symbol appears when using commandline definition without "="

[mikulas at artax dot karlin.mff.cuni.cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51745

--- Comment #4 from mikulas at artax dot karlin.mff.cuni.cz 2012-01-10 18:59:06 UTC ---
If you input garbage into a compiler, it should report an error, not output
garbage.