[cfe-dev] [Bug] Wrong Exception Handling : Destructor not called immediately

[Halfdan Ingvarsson]

Possibly related to this: http://llvm.org/bugs/show_bug.cgi?id=14223

We still compile specific projects with -O1 to get around this issue.

  - ½

On 14-04-04 12:39 PM, suyog sarda wrote:
> Gentle Ping !! Please help to verify if this is a bug and if my 
> analysis is correct.
>
>
> On Tue, Apr 1, 2014 at 10:18 PM, suyog sarda <sardask01 at gmail.com 
> <mailto:sardask01 at gmail.com>> wrote:
>
>     Hi all,
>
>     This is a test g++ test case for checking correct exception handling.
>
>     /#ifdef __GXX_EXPERIMENTAL_CXX0X__
>     #define NOEXCEPT_FALSE noexcept (false)
>     #else
>     #define NOEXCEPT_FALSE
>     #endif
>
>     extern "C" void abort ();
>
>     int thrown;
>
>     int as;
>     struct a {
>       a () { ++as; }
>       ~a () NOEXCEPT_FALSE { --as; if (thrown++ == 0) throw 42; }
>     };
>
>     int f (a const&) { return 1; }
>     int f (a const&, a const&) { return 1; }
>
>     int bs;
>     int as_sav;
>     struct b {
>       b (...) { ++bs; }
>       ~b ()   { --bs; as_sav = as; }
>     };
>
>     bool p;
>     void g()
>     {
>       if (p) throw 42;
>     }
>
>     int main () {
>       thrown = 0;
>       try {
>         b tmp(f (a(), a()));
>
>         g();
>       }
>       catch (...) {}
>
>       // We throw when the first a is destroyed, which should destroy
>     b before
>       // the other a.
>       if (as_sav != 1)
>         abort ();
>
>       thrown = 0;
>       try {
>         b tmp(f (a()));
>
>         g();
>       }
>       catch (...) {}
>
>       if (bs != 0)
>         abort ();
>     } /
>
>     This Test Case aborts on ARM as well as X86 with clang latest
>     trunk while with g++ no aborts are seen .
>
>     Here, when first temporary object '/a'/ gets destroyed, its
>     destructor is called where we throw an exception. This should
>     immediately call destructor of /'b'/ and before calling
>     constructor of second temporary object /'a'/. Instead, with clang,
>     it is waiting for second temporary object /'a'/ to get destroyed
>     and then calling its own destructor.
>
>     In my opinion, the compiler is not generating correct landing pad
>     for the exception. Can someone please help in validating this
>     reason? If it is a genuine bug then i will file a bug and try to
>     work out solution for it.
>
>     -- 
>     With regards,
>     Suyog Sarda
>
>
>
>
> -- 
> With regards,
> Suyog Sarda
>
>
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