[Bug c++/52320] New: missing destructor call after thrown exception in initializer

[Bug c++/52320] New: missing destructor call after thrown exception in initializer

[mmehlich at semanticdesigns dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

             Bug #: 52320
           Summary: missing destructor call after thrown exception in
                    initializer
    Classification: Unclassified
           Product: gcc
           Version: 4.5.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mmehlich@semanticdesigns.com


The following example has constructors of class A called 4 times but
destructors only 3 times. 

Apparently, if an exception is thrown during the construction of an aggregate
class, the destructors of already constructed data members are not called.

#include <iostream>

#define FUNCTION_NAME __PRETTY_FUNCTION__

#define TRACE_FUNCTION { std::cout << this << "->" << FUNCTION_NAME <<
std::endl; }

struct A {
    A() { TRACE_FUNCTION; }
    A(int) { TRACE_FUNCTION; }
    A(const A&) { TRACE_FUNCTION; }
    A &operator=(const A&) TRACE_FUNCTION;
    ~A() TRACE_FUNCTION;
};

int main() {
    try {
        struct X {
            A e1[2], e2;
        } 
        x2[3] = { 1, 2, 3, 4, (0, throw 9, 5), 6 };
    } catch (...) {
    }
}

Detailed version information:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-pc-cygwin/4.5.3/lto-wrapper.exe
Target: i686-pc-cygwin
Configured with:
/gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3/configure
--srcdir=/gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3
--prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin
--libexecdir=/usr/lib --datadir=/usr/share --localstatedir=/var
--sysconfdir=/etc --datarootdir=/usr/share --docdir=/usr/share/doc/gcc4 -C
--datadir=/usr/share --infodir=/usr/share/info --mandir=/usr/share/man -v
--with-gmp=/usr --with-mpfr=/usr --enable-bootstrap
--enable-version-specific-runtime-libs --libexecdir=/usr/lib --enable-static
--enable-shared --enable-shared-libgcc --disable-__cxa_atexit --with-gnu-ld
--with-gnu-as --with-dwarf2 --disable-sjlj-exceptions
--enable-languages=ada,c,c++,fortran,java,lto,objc,obj-c++ --enable-graphite
--enable-lto --enable-java-awt=gtk --disable-symvers --enable-libjava
--program-suffix=-4 --enable-libgomp --enable-libssp --enable-libada
--enable-threads=posix --with-arch=i686 --with-tune=generic
--enable-libgcj-sublibs CC=gcc-4 CXX=g++-4 CC_FOR_TARGET=gcc-4
CXX_FOR_TARGET=g++-4 GNATMAKE_FOR_TARGET=gnatmake GNATBIND_FOR_TARGET=gnatbind
--with-ecj-jar=/usr/share/java/ecj.jar
Thread model: posix
gcc version 4.5.3 (GCC)

[Bug c++/52320] missing destructor call after thrown exception in initializer

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler at
                   |                            |googlemail dot com

--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-02-21 08:26:30 UTC ---
Confirmed for 4.7.0 20120218 (experimental).

Reduced example with added information:

//----
#include <iostream>

#define FUNCTION_NAME __PRETTY_FUNCTION__

#define TRACE_FUNCTION(I) { std::cout << this << "->" << FUNCTION_NAME << "; i
= " << I << std::endl; }

struct A {
  int i;
  A(int i) : i(i) { TRACE_FUNCTION(i); }
  A(const A& rhs) : i(rhs.i) { TRACE_FUNCTION(i); }
  A &operator=(const A& rhs) { i = rhs.i; TRACE_FUNCTION(i); return *this; }
  ~A() { TRACE_FUNCTION(i); }
};

struct Y {
  A e1[2];
};

int main() {
  try {
    Y y1[1] = { {{1, (throw 0, 2)} } };
  } catch (int) {
  }
}
//----

Observed output is:

0x22fd60->A::A(int); i = 1

It does not happen when the local array y1 is replaced by a non-array Y.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

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

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-02-21 10:37:29 UTC ---
This looks similar to PR 41449 which Jason fixed

[Bug c++/52320] missing destructor call after thrown exception in initializer

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

--- Comment #3 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-02-21 10:53:59 UTC ---
(In reply to comment #2)

Agreed. It seems that the fix did not solve some array-related corner cases
like this one.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

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

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
commit r10-7110-g14af5d9b19b0f4ee1d929e505e245ae5c2f6bdc6
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Mar 10 16:05:18 2020 -0400

    c++: Partially revert patch for PR66139.

    The patch for 66139 exposed a long-standing bug with
    split_nonconstant_init (since 4.7, apparently): initializion of individual
    elements of an aggregate are not a full-expressions, but
    split_nonconstant_init was making full-expressions out of them.  My fix for
    66139 extended the use of split_nonconstant_init, and thus the bug, to
    aggregate initialization of temporaries within an expression, in which
    context (PR94041) the bug is more noticeable.  PR93922 is a problem with my
    implementation strategy of splitting out at gimplification time,
introducing
    function calls that weren't in the GENERIC.  So I'm going to revert the
    patch now and try again for GCC 11.

    gcc/cp/ChangeLog
    2020-03-10  Jason Merrill  <jason@redhat.com>

            PR c++/93922
            PR c++/94041
            PR c++/52320
            PR c++/66139
            * cp-gimplify.c (cp_gimplify_init_expr): Partially revert patch for
            66139: Don't split_nonconstant_init.  Remove pre_p parameter.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.0                        |10.2

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.1 has been released.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.2                        |10.3

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.2 is released, adjusting target milestone.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.3                        |10.4

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.3 is being released, retargeting bugs to GCC 10.4.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

--- Comment #12 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:4f6bc28fc7dd86bd9e7408cbf28de1e973dd1eda

commit r12-6329-g4f6bc28fc7dd86bd9e7408cbf28de1e973dd1eda
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Mar 5 15:50:45 2020 -0500

    c++: EH and partially constructed aggr temp [PR66139]

    Now that PR94041 is fixed, I can return to addressing PR66139, missing
    cleanups for partially constructed aggregate temporaries.  My previous
    approach of calling split_nonconstant_init in cp_gimplify_init_expr broke
    because gimplification is too late to be introducing destructor calls.  So
    instead I now call it under cp_fold_function, just before cp_genericize;
    doing it from cp_genericize itself ran into trouble with the rewriting of
    invisible references.

    So now the prediction in cp_gimplify_expr that cp_gimplify_init_expr
    might need to replace references to TARGET_EXPR_SLOT within
    TARGET_EXPR_INITIAL has come to pass.  constexpr.c already had the simple
    search-and-replace tree walk I needed, but it needed to be fixed to
actually
    replace all occurrences instead of just the first one.

    Handling of VEC_INIT_EXPR at gimplify time had similar issues that we
worked
    around with build_vec_init_elt, so I'm moving that to cp_fold_function as
    well.  But it seems that build_vec_init_elt is still useful for setting the
    VEC_INIT_EXPR_IS_CONSTEXPR flag, so I'm leaving it alone.

    This also fixes 52320, because build_aggr_init of each X from
build_vec_init
    builds an INIT_EXPR rather than call split_nonconstant_init at that point,
    and now that INIT_EXPR gets split later.

            PR c++/66139
            PR c++/52320

    gcc/cp/ChangeLog:

            * constexpr.c (replace_decl): Rename from replace_result_decl.
            * cp-tree.h (replace_decl): Declare it.
            * cp-gimplify.c (cp_gimplify_init_expr): Call it.
            (cp_gimplify_expr): Don't handle VEC_INIT_EXPR.
            (cp_genericize_init, cp_genericize_init_expr)
            (cp_genericize_target_expr): New.
            (cp_fold_r): Call them.
            * tree.c (build_array_copy): Add a TARGET_EXPR.
            * typeck2.c (digest_init_r): Look through a TARGET_EXPR.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/initlist116.C: New test.
            * g++.dg/cpp0x/initlist117.C: New test.
            * g++.dg/cpp0x/lambda/lambda-eh.C: New test.
            * g++.dg/eh/aggregate1.C: New test.

[Bug c++/52320] missing destructor call after thrown exception in initializer

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52320

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|10.0                        |
         Resolution|---                         |FIXED
   Target Milestone|10.4                        |12.0

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for GCC 12.