[boost] Regex lib bug: wrong alignment on 64 bit platforms

From: Benzinger, Ralph (ralph.benzinger_at_[hidden])
Date: 2004-08-24 11:50:41

Hello,

The regex library contains an alignment bug that leads to bus errors on 64 bit platforms (in particular, Sun and HP).  To reproduce, compile regular expression '(?>a+b|a+)bc+' with flags regex_constants::normal.  This should raise SIGBUS in perl_matcher<>::push_alt().

As a fix, I suggest forcing alignment of structure saved_state in perl_matcher_common.cpp:

   struct saved_state
   {
<     unsigned int id;
<     saved_state(unsigned i) : id(i) {}
->    union align
->    {
->      unsigned int id;
->      void* dummy;
->      align(unsigned i) : id(i) {}
->    } id_aligned;
->    saved_state(unsigned i) : id_aligned(i) {}
   };

and further down below:

<        unwinder = s_unwind_table[m_backup_state->id];
->       unwinder = s_unwind_table[m_backup_state->id_aligned.id];

The other saved_* structures that get pushed onto the stack seem fine for now.

Regards,
Ralph