• via Digitalmars-d-bugs (65/65) Aug 10 2015 https://issues.dlang.org/show_bug.cgi?id=14902

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=14902

          Issue ID: 14902
           Summary: Temporaries in argument expressions not properly
                    destructed on throw (argprefix)
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: kinke gmx.net

Created attachment 1540
  --> https://issues.dlang.org/attachment.cgi?id=1540&action=edit
Test cases

There are still major issues wrt. proper destruction of temporaries in
expression trees in case there are throws. These tests came up when verifying
an ongoing LDC implementation.
The attached file allows you to test 5 cases, by passing an arg in [1,5].
Case 1 doesn't feature any throw in the function argument expressions, but
features multiple objects with throwing dtors.
Case 2 throws in its last argument expression. The 3 preceeding temporaries
should be destructed.
Case 3 is similar to case 2, but 2 of the 3 temporaries throw in their dtors. I
guess this should result in all temporary dtors being called (always) and
building up an exception chain.
Case 4 already throws in its 2nd argument expression; the single preceeding
temporary doesn't throw in its dtor. Case 5 does throw.

Identical results with both DMD 2.067.1 and DMD 2.068-rc1 for Win32:

1) Fine - regular throw in callee, args have been implicitly moved into callee
params, callee destructs them. The exceptions in the dtors result in an
exception chain:

Test 1:
Constructing a
Constructing b
Constructing c
Constructing d
Destroying a
Destroying b
Destroying c
Destroying d
object.Exception ..\dtor.d(26): foo()!
object.Exception ..\dtor.d(16): dtor a
object.Exception ..\dtor.d(16): dtor c

2&3) No temporaries destructed at all!

Test 2&3:
Constructing a
Constructing b
Constructing c
object.Exception ..\dtor.d(22): make(d)

4) Fine, at last.

Test 4:
Constructing a
Destroying a
object.Exception ..\dtor.d(22): make(b)

5) CRASH at runtime!

Test 5:
Constructing
Destroying a
Destroying a
...
<repetition until crash>

--