[Bug preprocessor/30805] New: Internal compiler error when using "x##,##__VA_ARGS__" in macro

[Bug preprocessor/30805] New: Internal compiler error when using "x##,##__VA_ARGS__" in macro

[johandefries at gmail dot com]

The 2-line source that triggers the error:

#define A(x,...) x##,##__VA_ARGS__
A(1)

Error message:
a.c:6: internal compiler error: Geannuleerd
Please submit a full bug report

The source file is from:
http://www.kernel.org/git/?p=linux/kernel/git/josh/sparse.git;a=blob;f=validation/preprocessor13.c;hb=0.2

My system:
Linux Knoppix 2.6.19 #7 SMP PREEMPT Sun Dec 17 22:01:07 CET 2006 i686 GNU/Linux

The bug is triggerd by al 4 compilers on my system. 
gcc-3.3 (GCC) 3.3.6 (Debian 1:3.3.6-13)
gcc-3.4 (GCC) 3.4.6 (Debian 3.4.6-4)
gcc-4.0 (GCC) 4.0.4 20060904 (prerelease) (Debian 4.0.3-7)
gcc-4.1 (GCC) 4.1.2 20061028 (prerelease) (Debian 4.1.1-19)


-- 
           Summary: Internal compiler error when using "x##,##__VA_ARGS__"
                    in macro
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: johandefries at gmail dot com
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2007-02-16 01:34 -------
3.0.4 and 2.95.3 did not ICE on this.  Confirmed a regression.  I don't know if
this is valid or not.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
      Known to fail|                            |3.3.3 4.1.2 4.2.0 4.0.4
      Known to work|                            |3.0.4 2.95.3
   Last reconfirmed|0000-00-00 00:00:00         |2007-02-16 01:34:25
               date|                            |
            Summary|Internal compiler error when|[4.1/4.2/4.3 Regression]
                   |using "x##,##__VA_ARGS__" in|Internal compiler error when
                   |macro                       |using "x##,##__VA_ARGS__" in
                   |                            |macro
   Target Milestone|---                         |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[mmitchel at gcc dot gnu dot org]

------- Comment #2 from mmitchel at gcc dot gnu dot org  2007-02-19 21:09 -------
Joseph --

Is this valid code?

Thanks,

-- Mark


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |joseph at codesourcery dot
                   |                            |com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[joseph at codesourcery dot com]

------- Comment #3 from joseph at codesourcery dot com  2007-02-19 22:20 -------
Subject: Re:  [4.1/4.2/4.3 Regression] Internal
 compiler error when using "x##,##__VA_ARGS__" in macro

The order of evaluation of ## operators is unspecified.

If the left ## is evaluated first, it tries to concatenate "1" with ",", 
yielding undefined behavior (for some time GCC has diagnosed such attempts 
at concatenation yielding invalid preprocessing tokens).  If the right ## 
is evaluated first, the GNU extension for concatenation of "," with empty 
__VA_ARGS__ is engaged; this presumably should leave a placemarker token, 
whose concatenation with "1" yields "1".


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[mmitchel at gcc dot gnu dot org]

------- Comment #4 from mmitchel at gcc dot gnu dot org  2007-03-05 03:55 -------
The fact that the result is in any case unspecified, coupled with the obscurity
of the code, makes this a P2.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[bonzini at gnu dot org]

------- Comment #5 from bonzini at gnu dot org  2007-04-16 20:10 -------
What about a patch like this?

Index: macro.c
===================================================================
--- macro.c     (revision 123691)
+++ macro.c     (working copy)
@@ -499,9 +499,15 @@ paste_all_tokens (cpp_reader *pfile, con
        rhs = *FIRST (context).ptoken++;

       if (rhs->type == CPP_PADDING)
-       abort ();
+       {
+         /* In obscure cases where the GNU extension ,##__VA_ARGS__ is
+            used, we can get a CPP_PADDING token here.  Assert that we
+            can safely ignore it.  */
+         if (rhs->flags & PASTE_LEFT)
+           abort ();
+       }

-      if (!paste_tokens (pfile, &lhs, rhs))
+      else if (!paste_tokens (pfile, &lhs, rhs))
        break;
     }
   while (rhs->flags & PASTE_LEFT);


-- 

bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[tromey at gcc dot gnu dot org]

------- Comment #6 from tromey at gcc dot gnu dot org  2007-10-31 17:37 -------
This patch makes gcc enter an infinite loop rather than ICEing.


-- 

tromey at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[tromey at gcc dot gnu dot org]

------- Comment #7 from tromey at gcc dot gnu dot org  2007-10-31 19:12 -------
I'm testing a revised patch.


-- 

tromey at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |tromey at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-08-06 15:06:47         |2007-10-31 19:12:33
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2/4.3 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[tromey at gcc dot gnu dot org]

------- Comment #8 from tromey at gcc dot gnu dot org  2007-11-01 18:21 -------
Subject: Bug 30805

Author: tromey
Date: Thu Nov  1 18:20:48 2007
New Revision: 129827

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129827
Log:
libcpp
        PR preprocessor/30805:
        * macro.c (paste_tokens): Handle padding token.
        (paste_tokens): Don't abort unless padding has PASTE_LEFT flag.
gcc/testsuite
        PR preprocessor/30805:
        * gcc.dg/cpp/pr30805.c: New file.

Added:
    trunk/gcc/testsuite/gcc.dg/cpp/pr30805.c
Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/libcpp/ChangeLog
    trunk/libcpp/macro.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[jakub at gcc dot gnu dot org]

------- Comment #9 from jakub at gcc dot gnu dot org  2007-11-01 18:27 -------
Fixed on the trunk.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|3.0.4 2.95.3                |3.0.4 2.95.3 4.3.0
            Summary|[4.1/4.2/4.3 Regression]    |[4.1/4.2 Regression]
                   |Internal compiler error when|Internal compiler error when
                   |using "x##,##__VA_ARGS__" in|using "x##,##__VA_ARGS__" in
                   |macro                       |macro


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[jakub at gcc dot gnu dot org]

------- Comment #10 from jakub at gcc dot gnu dot org  2007-11-01 23:25 -------
The testcase fails btw:
Executing on host: /usr/src/gcc/obj/gcc/xgcc -B/usr/src/gcc/obj/gcc/
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c    -ansi -pedantic-errors
-fno-show-column -E  -o pr30805.i    (timeout = 300)
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:4: error: anonymous variadic
macros were introduced in C99
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:5: error: ISO C99 requires rest
arguments to be used
compiler exited with status 1
output is:
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:4: error: anonymous variadic
macros were introduced in C99
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:5: error: ISO C99 requires rest
arguments to be used

FAIL: gcc.dg/cpp/pr30805.c (test for excess errors)
Excess errors:
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:4: error: anonymous variadic
macros were introduced in C99
/usr/src/gcc/gcc/testsuite/gcc.dg/cpp/pr30805.c:5: error: ISO C99 requires rest
arguments to be used

If I add
/* { dg-options "-std=gnu99" } */
(or -std=gnu89 or -std=c99), then it fails with:
pr30805.c:6: error: expected identifier or `(' before numeric constant
It doesn't ICE in either case (and ICEd with older cc1).  Now if the above
error message is correct, we should add the dg-options line and dg-error for
this error.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[tromey at gcc dot gnu dot org]

------- Comment #11 from tromey at gcc dot gnu dot org  2007-11-01 23:34 -------
Sorry about that.  I don't know what went wrong.
The test should only be preprocessed, not compiled.
I will fix this.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.1/4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[tromey at gcc dot gnu dot org]

------- Comment #12 from tromey at gcc dot gnu dot org  2007-11-01 23:39 -------
Subject: Bug 30805

Author: tromey
Date: Thu Nov  1 23:38:52 2007
New Revision: 129838

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129838
Log:
        PR preprocessor/30805:
        * gcc.dg/cpp/pr30805.c: Use -std=gnu89.

Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/cpp/pr30805.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[jsm28 at gcc dot gnu dot org]

------- Comment #13 from jsm28 at gcc dot gnu dot org  2008-07-04 21:57 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.1/4.2 Regression]        |[4.2 Regression] Internal
                   |Internal compiler error when|compiler error when using
                   |using "x##,##__VA_ARGS__" in|"x##,##__VA_ARGS__" in macro
                   |macro                       |
   Target Milestone|4.1.3                       |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805

[Bug preprocessor/30805] [4.2 Regression] Internal compiler error when using "x##,##__VA_ARGS__" in macro

[jsm28 at gcc dot gnu dot org]

------- Comment #14 from jsm28 at gcc dot gnu dot org  2009-03-30 21:34 -------
Closing 4.2 branch, fixed in 4.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|3.3.3 4.1.2 4.2.0 4.0.4     |3.3.3 4.1.2 4.2.0 4.0.4
                   |                            |4.2.5
         Resolution|                            |FIXED
   Target Milestone|4.2.5                       |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30805