[Bug c++/48370] New: G++ fails to extend reference temporary lifetime in some situations

[Bug c++/48370] New: G++ fails to extend reference temporary lifetime in some situations

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48370

           Summary: G++ fails to extend reference temporary lifetime in
                    some situations
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jason@gcc.gnu.org


In addition to the issue described in bug 26714, we fail to extend the
temporary lifetime if the reference we're binding to is a subobject:

extern "C" void abort();
bool ok;

struct A {
  A(int) { }
  ~A() { if (!ok) abort(); }
};

struct C
{
  const A& ar;
};

int main()
{
  C c = { 1 };
  ok = true;
}

This problem is more severe in C++0x, where you can have initializer_list
subobjects:

// Test that we properly extend the lifetime of the initializer_list
// array even if the initializer_list is a subobject.
// { dg-options -std=c++0x }
// { dg-do run }

#include <initializer_list>

extern "C" void abort();
bool ok;

struct A {
  A(int) { }
  ~A() { if (!ok) abort(); }
};

typedef std::initializer_list<A> AL;
typedef std::initializer_list<AL> AL2;
typedef std::initializer_list<AL2> AL3;

struct B {
  AL al;
  const AL& alr;
};

int main()
{
  AL ar[] = {{1,2},{3,4}};
  B b = {{5,6},{7,8}};
  AL3 al3 = {{{1},{2},{3}}};
  ok = true;
}

[Bug c++/48370] G++ fails to extend reference temporary lifetime in some situations

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48370

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danny.dyk@tu-dortmund.de

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> 2011-08-08 13:54:30 UTC ---
*** Bug 50015 has been marked as a duplicate of this bug. ***

[Bug c++/48370] G++ fails to extend reference temporary lifetime in some situations

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48370

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-04 12:54:14 UTC ---
Author: jason
Date: Fri Nov  4 12:54:08 2011
New Revision: 180944

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180944
Log:
    PR c++/48370
    * call.c (extend_ref_init_temps, extend_ref_init_temps_1): New.
    (set_up_extended_ref_temp): Use it.  Change cleanup parm to VEC.
    (initialize_reference): Just call convert_like.
    * decl.c (grok_reference_init): Just call initialize_reference.
    (build_init_list_var_init): Remove.
    (check_initializer): Change cleanup parm to VEC.  Handle references
    like other types.  Call perform_implicit_conversion instead
    of build_init_list_var_init.  Don't use build_aggr_init for
    aggregate initialization of arrays.
    (cp_finish_decl): Change cleanup to VEC.
    * typeck2.c (store_init_value): Call extend_ref_init_temps.
    Use build_vec_init for non-constant arrays.
    * init.c (expand_aggr_init_1): Adjust.
    (build_vec_init): Avoid re-converting an initializer
    that's already digested.
    * mangle.c (mangle_ref_init_variable): Add a discriminator.
    * cp-tree.h: Adjust.
    * typeck.c (convert_for_initialization): Adjust.
    * decl2.c (maybe_emit_vtables): Adjust.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/initlist-lifetime1.C
    trunk/gcc/testsuite/g++.dg/eh/array1.C
    trunk/gcc/testsuite/g++.dg/init/lifetime1.C
    trunk/gcc/testsuite/g++.dg/init/ref21.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/decl2.c
    trunk/gcc/cp/init.c
    trunk/gcc/cp/mangle.c
    trunk/gcc/cp/typeck.c
    trunk/gcc/cp/typeck2.c
    trunk/gcc/testsuite/ChangeLog
    trunk/libiberty/ChangeLog
    trunk/libiberty/cp-demangle.c

[Bug c++/48370] G++ fails to extend reference temporary lifetime in some situations

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48370

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-04 14:45:48 UTC ---
Fixed for 4.7.

[Bug c++/48370] G++ fails to extend reference temporary lifetime in some situations

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48370

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-05 03:28:09 UTC ---
Author: jason
Date: Sat Nov  5 03:28:05 2011
New Revision: 181001

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=181001
Log:
    PR c++/48370
    * decl.c (cp_finish_decl): Run cleanups in the right order.

Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/init/lifetime1.C