Types table size and format in the .gcc_exception_table

Types table size and format in the .gcc_exception_table

[Shahid Alam]

As part of my research I am updating the .gcc_exception_table of a 
binary 64 bit elf file. For small C++ programs that throw exceptions it 
works OK, but for large benchmark programs it's not working. My question 
is does GCC stores more than one table inside the .gcc_exception_table 
section of the elf file. If it does what's the exact format of these 
tables. I have some knowledge of the action table, action records and 
types table. I am not clear about the size of the types table.

I am parsing the tables in this section but is not able to know the 
exact size and format of the types tables, where a pointer to the 
exception information is stored. I need to update this pointer to the 
new updated location.

Any help is appreciated.
Thanks,
-- Shahid

Re: Types table size and format in the .gcc_exception_table

[Ian Lance Taylor]

On Mon, Jan 7, 2013 at 1:13 PM, Shahid Alam <alam_shahid@yahoo.com> wrote:
> As part of my research I am updating the .gcc_exception_table of a binary 64
> bit elf file. For small C++ programs that throw exceptions it works OK, but
> for large benchmark programs it's not working. My question is does GCC
> stores more than one table inside the .gcc_exception_table section of the
> elf file. If it does what's the exact format of these tables. I have some
> knowledge of the action table, action records and types table. I am not
> clear about the size of the types table.
>
> I am parsing the tables in this section but is not able to know the exact
> size and format of the types tables, where a pointer to the exception
> information is stored. I need to update this pointer to the new updated
> location.

I documented the .gcc_except_table section at
http://www.airs.com/blog/archives/464 .

Yes, there is normally more than one table (one LSDA) in the
.gcc_except_table section.  There is normally one LSDA per function
that needs to handle exceptions.  Each such function will have a
pointer to the LSDA in its FDE entry in the .eh_frame section, as
described at http://www.airs.com/blog/archives/460 .

Ian