[Bug c++/15745] New: exception specification incorrectly changes the type of the exception thrown

[Bug c++/15745] New: exception specification incorrectly changes the type of the exception thrown

[wsf at fultondesigns dot co dot uk]

$ cat gccexceptionbug.cxx

#include <iostream>
using namespace std;

typedef int IntArray[10];

void test_array() throw (IntArray) {
//void test_array() {
    static IntArray arr;
    for (int i=0; i<10; i++) {
        arr[i] = i;
    }
    throw arr;
}

int main ()
{
    cout << "Start" << endl;

    try {
        test_array();
    } catch (IntArray) {
        cout << "Caught!" << endl;
    }

    cout << "Finish" << endl;

    return 0;
}


$ g++-3.4.0 -v -save-temps gccexceptionbug.cxx -o gccexceptionbug
Reading specs from /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/specs
Configured with: ../configure --prefix=/usr --libdir=/usr/lib
--with-slibdir=/lib --mandir=/usr/share/man --infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --enable-long-long
--enable-__cxa_atexit --enable-clocale=gnu --disable-libunwind-exceptions
--enable-languages=c,c++,java --program-suffix=-3.4.0
--host=i586-mandrake-linux-gnu --with-system-zlib
Thread model: posix
gcc version 3.4.0 (Mandrake Linux 10.0 3.4.0-1mdk)
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/cc1plus -E -quiet -v -D_GNU_SOURCE
gccexceptionbug.cxx -mtune=pentium -o gccexceptionbug.ii
ignoring nonexistent directory
"/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../../i586-mandrake-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../../include/c++/3.4.0
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../../include/c++/3.4.0/i586-mandrake-linux-gnu
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../../include/c++/3.4.0/backward
 /usr/local/include
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/include
 /usr/include
End of search list.
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/cc1plus -fpreprocessed
gccexceptionbug.ii -quiet -dumpbase gccexceptionbug.cxx -mtune=pentium -auxbase
gccexceptionbug -version -o gccexceptionbug.s
GNU C++ version 3.4.0 (Mandrake Linux 10.0 3.4.0-1mdk) (i586-mandrake-linux-gnu)
        compiled by GNU C version 3.4.0 (Mandrake Linux 10.0 3.4.0-1mdk).
GGC heuristics: --param ggc-min-expand=47 --param ggc-min-heapsize=32000
 as -V -Qy -o gccexceptionbug.o gccexceptionbug.s
GNU assembler version 2.14.90.0.5 (i586-mandrake-linux-gnu) using BFD version
2.14.90.0.5 20030722
 /usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/collect2 --eh-frame-hdr -m elf_i386
-dynamic-linker /lib/ld-linux.so.2 -o gccexceptionbug
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../crt1.o
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../crti.o
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/crtbegin.o
-L/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0
-L/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0
-L/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../.. gccexceptionbug.o -lstdc++
-lm -lgcc_s -lgcc -lc -lgcc_s -lgcc
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/crtend.o
/usr/lib/gcc/i586-mandrake-linux-gnu/3.4.0/../../../crtn.o
$
$ ./gccexceptionbug
Start
terminate called after throwing an instance of 'int*'
Aborted
$


Note that if  the exception specification in the definition of test_array() is
removed, the exception is caught. (Replace with the commented out line). The
same behaviour was observed in gcc version 3.3.1 (cygming special).

-- 
           Summary: exception specification incorrectly changes the type of
                    the exception thrown
           Product: gcc
           Version: 3.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: wsf at fultondesigns dot co dot uk
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i586-mandrake-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-05-31 13:15 -------
If I recall correctly from my reading of the standard arrays get decayed to pointers for things like this 
(and a couple of others too).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-06-01 15:27 -------
Confirmed. Here's a small testcase: 
------------------- 
typedef int IntArray[10]; 
IntArray i; 
 
void test_array() 
#ifdef TEST 
  throw (IntArray) 
#endif 
{ throw i; } 
 
 
int main () { 
    try { 
        test_array(); 
    } catch (IntArray) {} 
} 
------------------ 
 
We get 
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ x.cc ; ./a.out  
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ x.cc -DTEST ; ./a.out  
terminate called after throwing an instance of 'int*' 
Aborted 
 
The point is that if we throw an exception that violates the exception 
specification, then it is converted into an unspec exception and we 
abort. However, since we can catch the exception that we throw in the  
main function if there is no exception specification on the function 
body, it seems as if the exception thrown is really of type IntArray 
and shouldn't violate the exception specification. I agree that this 
is confusing and looks like a bug in gcc associated with decaying 
arrays to pointers, though I'd like to solicit a second opinion on 
this. 
 
We get the same results for all gcc versions from 2.95 to mainline. 
 
W. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
      Known to fail|                            |2.95.3 3.3.1 3.0.4 3.4.0
                   |                            |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-26 20:22 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-06-26 20:22:14
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[jason at gcc dot gnu dot org]

------- Comment #4 from jason at gcc dot gnu dot org  2007-09-06 03:33 -------
Subject: Bug 15745

Author: jason
Date: Thu Sep  6 03:33:46 2007
New Revision: 128174

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=128174
Log:
        PR c++/15745
        * except.c (prepare_eh_type): Use type_decays_to.

Added:
    trunk/gcc/testsuite/g++.dg/eh/spec9.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/except.c
    trunk/gcc/testsuite/g++.dg/ext/vla4.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[jason at gcc dot gnu dot org]

------- Comment #5 from jason at gcc dot gnu dot org  2007-10-01 20:53 -------
Subject: Bug 15745

Author: jason
Date: Mon Oct  1 20:53:09 2007
New Revision: 128917

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=128917
Log:
        PR c++/15745
        * except.c (prepare_eh_type): Use type_decays_to.

Modified:
    branches/gcc-4_2-branch/gcc/testsuite/g++.dg/ext/vla4.C


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745

[Bug c++/15745] exception specification incorrectly changes the type of the exception thrown

[jason at gcc dot gnu dot org]

------- Comment #6 from jason at gcc dot gnu dot org  2008-11-18 18:50 -------
Fixed.


-- 

jason at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15745