[Bug c++/61611] New: Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[Bug c++/61611] New: Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[bspencer at blackberry dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

            Bug ID: 61611
           Summary: Incorrect exception rethrown from a function-try-catch
                    block when a nested try-catch executes
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bspencer at blackberry dot com

Created attachment 33006
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33006&action=edit
Test program demonstrating the issue

In a try-catch (catch) block nested within, but separate from, a
function-try-catch (catch) block, gcc 4.7.2 for Linux (Debian) and gcc 4.8 for
Linux are both incorrectly re-throwing the exception caught inside the nested
catch block as that nested catch block exits.

Attached is a program that shows the error when compiled with -DFUNCTION_TRY

The program prints "PASS" when the correct exception propagates and and "FAIL"
when the incorrect exception propagates.

Note that this does not appear to be the behaviour of

15.3/15: "The currently handled exception is rethrown if control reaches the
end of a handler of the function-try-block of a constructor or destructor."

because the control is not reaching the end of such a handler.  Thus, this
report differs from Bug #45481.

Perhaps _all_ catch blocks (including nested catch blocks) in a constructor
function try-catch are rethrowing when control reaches the end of them instead
of only the catch blocks of the actual constructor function try-catch
structure.

$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.7.2-5'
--with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object
--enable-plugin --enable-objc-gc --with-arch-32=i586 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.2 (Debian 4.7.2-5)

$ g++ -Wall -o test test.cc
$ ./test
main() starts
Caught out_of_range: out_of_range
Caught length_error: length_error
Re-throw original ex
TOP Caught out_of_range: out_of_range
PASS
main() stops

$ g++ -Wall -o test test.cc -DFUNCTION_TRY
$ ./test
main() starts
Caught out_of_range: out_of_range
Caught length_error: length_error
TOP Caught length_error: length_error
FAIL
main() stops

The attched program passes with clang++ (clang-503.0.40) with or without
-DFUNCTION_TRY.

Apologies for the non-preprocessed test file, but it does use only standard
headers.

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-06-25
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Brad Spencer from comment #0)
> Perhaps _all_ catch blocks (including nested catch blocks) in a constructor
> function try-catch are rethrowing when control reaches the end of them
> instead of only the catch blocks of the actual constructor function
> try-catch structure.

Yes, that seems to be the case.

> Apologies for the non-preprocessed test file, but it does use only standard
> headers.

That's fine, but personally I find it more useful if the testcase shows the bug
by default, and a macro is needed to make it pass.

Reduced:

struct A { };
struct B { };

class Test
{
public:
  Test()
  try
  {
    throw A();
  }
  catch(const A&)
  {
    try
    {
      throw B();
    } catch(const B&) {
    }
  }
};

int
main()
{
  try
  {
    Test x;
  }
  catch(const A&)
  {
  }
}

This should terminate normally.

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org
             Status|NEW                         |ASSIGNED
                 CC|                            |jason at gcc dot gnu.org

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:6ad76e73375a9c00a0a5f5729ae70bce7a6db5bc

commit r12-6334-g6ad76e73375a9c00a0a5f5729ae70bce7a6db5bc
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jan 6 09:45:26 2022 -0500

    c++: nested catch in ctor fn-try-block [PR61611]

    Being in_function_try_handler isn't enough to satisfy the condition of
    reaching the end of such a handler; in this case, we're reaching the end of
    a handler within that handler, so we don't want the special semantics.

            PR c++/61611

    gcc/cp/ChangeLog:

            * except.c (in_nested_catch): New.
            (expand_end_catch_block): Check it.

    gcc/testsuite/ChangeLog:

            * g++.dg/eh/ctor-fntry1.C: New test.

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.0
      Known to work|                            |12.0

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for GCC 12 so far.  Is there interest in having the fix in other release
branches?

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:cfcf6459810b010e8af2798581967872f68f1178

commit r11-9521-gcfcf6459810b010e8af2798581967872f68f1178
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jan 6 09:45:26 2022 -0500

    c++: nested catch in ctor fn-try-block [PR61611]

    Being in_function_try_handler isn't enough to satisfy the condition of
    reaching the end of such a handler; in this case, we're reaching the end of
    a handler within that handler, so we don't want the special semantics.

            PR c++/61611

    gcc/cp/ChangeLog:

            * except.c (in_nested_catch): New.
            (expand_end_catch_block): Check it.

    gcc/testsuite/ChangeLog:

            * g++.dg/eh/ctor-fntry1.C: New test.

[Bug c++/61611] Incorrect exception rethrown from a function-try-catch block when a nested try-catch executes

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61611

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|12.0                        |11.3
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 11.3/12.