More SJLJ exception breakage

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Hello,

it seems SJLJ exception handling is broken again (at least on SPU).  The
most obvious symptom is that libstdc++ "operator new" is miscompiled.

A reduced test case would be:

typedef long unsigned int size_t;
extern "C" void * malloc (size_t __size);

class bad_alloc
{
  public:
    bad_alloc() throw() { }
    virtual ~bad_alloc() throw();
    virtual const char* what() const throw();
};

void *
operator new (size_t sz) throw (bad_alloc)
{
  void *p;

  p = (void *) malloc (sz);
  if (p == 0)
    throw bad_alloc();

  return p;
}

Building this with -O2 results in:

        brsl    $lr,malloc      ;# 7    _call_value/2   [length = 4]
        brz     $3,.L8  ;# 10   *spu.md:3590    [length = 4]
#note result of malloc is in register $r3  (the branch goes to the throw case)

        ai      $3,$sp,48       ;# 87   addsi3/2        [length = 4]
        brsl    $lr,_Unwind_SjLj_Unregister     ;# 88   _call/2 [length = 4]
#which is clobbered here with the argument passed to _Unwind_SjLj_Unregister

        ai      $sp,$sp,176     ;# 160  addsi3/2        [length = 4]
        lqd     $lr,16($sp)     ;# 162  _movv4si/5      [length = 4]
        lqd     $127,-16($sp)   ;# 161  _movv4si/5      [length = 4]
        bi      $lr     ;# 164  _return [length = 4]
#and never restored on its way out

The RTL is broken already in ...133r.eh:

(code_label 32 31 41 10 1 "" [1 uses])

(note 41 32 33 10 [bb 10] NOTE_INSN_BASIC_BLOCK)

(insn 33 41 39 10 new_op.ii:23 (set (reg/i:SI 3 $3)
        (reg:SI 138 [ <result> ])) -1 (nil))

(insn 39 33 86 10 new_op.ii:23 (use (reg/i:SI 3 $3)) -1 (nil))

(insn 86 39 87 10 (set (reg:SI 186)
        (plus:SI (reg/f:SI 132 virtual-stack-vars)
            (const_int -112 [0xffffffffffffff90]))) -1 (nil))

(insn 87 86 88 10 (set (reg:SI 3 $3)
        (reg:SI 186)) -1 (nil))

(call_insn 88 87 0 10 (parallel [
            (call (mem:QI (symbol_ref:SI ("_Unwind_SjLj_Unregister") [flags 0x41]) [0 S1 A8])
                (const_int 0 [0x0]))
            (clobber (reg:SI 0 $lr))
            (clobber (reg:SI 130 hbr))
        ]) -1 (expr_list:REG_EH_REGION (const_int 0 [0x0])
        (nil))
    (expr_list:REG_DEP_TRUE (use (reg:SI 3 $3))
        (nil)))

It would appear the call to _Unwind_SjLj_Unregister is simply inserted
too late; it needs to take place *before* the result register is set up
(insn 33), not afterwards.


Any idea why this might happen or suggestions what else to check? 

Thanks,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com