[LLVMdev] how to reslove gcc_except_table?

[zhengjian zhang]

Hi,

   123          .byte   0x3
   124          .byte   0x7d

where 0x3 means that the typeinfo is _ZTIi (int).
The 0x7d says that if the typeinfo doesn't match,
then the next action to consider is at offset -3
from here.  In other words, it will continue with



2009/3/13 Duncan Sands <baldrick at free.fr>:
> Hi,
>
>>     maybe this should not be here!
>
> does this have anything to do with LLVM?


>> int main()
>> {
>>     try {
>>         throw 34;
>>     }
>>     catch (int) {
>>     }
>>     catch (char) {
>>     }
>>     catch (bool) {
>>     }
>> }
>
> The action is 0x5, this refers to
>
>    123          .byte   0x3
>    124          .byte   0x7d
>
> where 0x3 means that the typeinfo is _ZTIi (int).
> The 0x7d says that if the typeinfo doesn't match,
> then the next action to consider is at offset -3
> from here.  In other words, it will continue with

>>
>
>    121          .byte   0x2
>    122          .byte   0x7d
>
> i.e. it will then try and match with _ZTIc.  If this
> doesn't match then the next action to consider is
> offset -3 from here (0x7d), i.e. it will next examine
>
>    119          .byte   0x1     # Action record table
>    120          .byte   0x0
>
> i.e. it will try and match with _ZTIb.  If this
> doesn't match then it is all over (0x0).
>
>>    116          .uleb128 0x0    # region 0 landing pad
>>    117          .uleb128 0x5    # action
>>    118  .LLSDACSE2:
>>    119          .byte   0x1     # Action record table
>>    120          .byte   0x0
>>    121          .byte   0x2
>>    122          .byte   0x7d
>>    123          .byte   0x3
>>    124          .byte   0x7d
>>    125          .align 4
>>    126          .long   _ZTIi
>>    127          .long   _ZTIc
>>    128          .long   _ZTIb
>>    129  .LLSDATT2:
>>
>>
>> ok: my problem is the action(line 117) how to index to the action record table?
>>       in Action record table , why there are the magic 0x7d?.
>
> Ciao,
>
> Duncan.
>