Proposed Patch for Bug 69687

[Manuel López-Ibáñez]

On 03/03/16 14:21, Bernd Schmidt wrote:
> On 03/02/2016 06:22 PM, Mike Stump wrote:
>>
>> So, check for overflow, or better use unsigned values that are large
>> enough to never overflow.  With no possibility for overflow, you can
>> then retest the bug and see if there are any other failure modes and
>> fix those.
>
> What C standard can we assume for libiberty? I was looking@patching this and
> discovered that SIZE_MAX is defined only for C99, so I'm leaning towards
> retaining the ints and using INT_MAX.

Retaining INT_MAX should be ok in this case, since that should allow pretty 
large mangled strings. As far as I know, the only users of libiberty are GDB 
and GCC, and GDB only because they have not completely moved to gnulib yet. GCC 
is C++, GDB assumes C90 but it is moving to C++ anyway, so it could be bumped 
to SIZE_MAX later.

However, it would be much better to add to libiberty something like gnulib's 
x2realloc and x2nrealloc and use that because:

* It is more concise.
* Avoid duplication.
* libiberty should be replaced by gnulib eventually
* error-handling is shared with xrealloc, which gives both more consistency and 
more flexibility.

Of course, there is an even better fix: Add to the GCC repository enough gnulib 
modules to use directly the x2realloc from gnulib, make the demangler use that. 
GDB is already using some gnulib modules, so it should not be a problem for 
them. It is a bit more work in the short term, but re-implementing function by 
function a lower quality implementation of the whole gnulib seems much worse in 
the long run.

Cheers,

	Manuel.