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

[Richard Smith]

See:

  http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-June/050886.html

... where this exact testcase was last discussed.

On Fri, Apr 4, 2014 at 9:39 AM, suyog sarda <sardask01 at gmail.com> 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> wrote:
>
>> Hi all,
>>
>> This is a test g++ test case for checking correct exception handling.
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>> *#ifdef __GXX_EXPERIMENTAL_CXX0X__#define NOEXCEPT_FALSE noexcept
>> (false)#else #define NOEXCEPT_FALSE#endifextern "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 ();} *
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>> 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
>>
>
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> --
> With regards,
> Suyog Sarda
>
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>
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