[Bug libstdc++/12873] New: __cxa_demangle not working as specified in ABI

[Bug libstdc++/12873] New: __cxa_demangle not working as specified in ABI

[rmerkert at alphatech dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873

           Summary: __cxa_demangle not working as specified in ABI
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rmerkert at alphatech dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: gcc (GCC) 3.4 20031026 (experimental)

This test program produces different results for 3.3.2 and 3.4.

cat > test.c <<EOF
#include <stdio.h>
#include <stdlib.h>

extern char *__cxa_demangle (const char *__mangled_name,
                             char *__output_buffer,
                             __SIZE_TYPE__ *__length,
                             int *__status);


int main(int argc, char** argv)
{
  for (int i=1;i<argc;++i) {
    int status;
    char* res = __cxa_demangle(argv[i],0,0,&status);
    if (res!=NULL || status!=0) {
      printf("Demangled '%s' as '%s'\n",argv[i],res);
    }
    else {
      printf("Could not demangle '%s'\n",argv[i]);
    }
    free(res);
  }
  return 0;
}

EOF

/local/gcc/bin/gcc -o test test.c -std=c99 /local/gcc/lib/libstdc++.a

'./test hello'

produces

Demangled 'hello' as 'unsigned char'

Also, if I don't pass the status flag pointer, then  I get 

Could not demangle 'hello'


Code is working in mainline, but it would be nice to have it work in 3.3
release series as well. 

Can this be backported?

[Bug libstdc++/12873] __cxa_demangle not working as specified in 3.3.2 ABI

[rmerkert at alphatech dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873


rmerkert at alphatech dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|__cxa_demangle not working  |__cxa_demangle not working
                   |as specified in ABI         |as specified in 3.3.2 ABI

[Bug libstdc++/12873] __cxa_demangle not working as specified in 3.3.2 ABI

[rmerkert at alphatech dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873


rmerkert at alphatech dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  GCC build triplet|gcc (GCC) 3.4 20031026      |gcc (GCC) 3.3.2
                   |(experimental)              |

[Bug libstdc++/12873] __cxa_demangle not working as specified in 3.3.2 ABI

[carlo at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873


carlo at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-11-02 02:21:55
               date|                            |


------- Additional Comments From carlo at gcc dot gnu dot org  2003-11-02 02:21 -------
The demangler in 3.4 is a complete rewrite, it cannot be
back ported.  What needs to be fixed here is that the
__cxa_demangle implementation in 3.3

1) Doesn't take the string length of the input into account
   (ie, it demangles what it can and ignores any trailing
    characters).  It should fail if any characters are trailing.
2) A single character should NOT be considered to be a mangled
   type name (a builtin-type) - but returned as-is.

Instead, it demangles the 'h' and ignores the rest.

I am afraid I have no time to write patches for the 3.3 branch,
but I am sure this would be a small patch.

[Bug libstdc++/12873] [3.3 only] __cxa_demangle not working as specified in 3.3.2 ABI

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|__cxa_demangle not working  |[3.3 only] __cxa_demangle
                   |as specified in 3.3.2 ABI   |not working as specified in
                   |                            |3.3.2 ABI
   Target Milestone|---                         |3.3.3

[Bug libstdc++/12873] [3.3 only] __cxa_demangle not working as specified in 3.3.2 ABI

[bkoz at gcc dot gnu dot org]

------- Additional Comments From bkoz at gcc dot gnu dot org  2003-12-05 07:04 -------

The 3.3.x __cxa_demangle code is considered broken. It's been re-written a
couple of times now.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12873