Re: [Bug-apl] More Solaris porting issues

[Markus Gothe]

Usually the stack frame has a platform specific (!!!) size. If you overflow the stack return adress, stack pointers etc maybe fuzzed.

It is generally a bad idea with heritage from the old VAXen era. IIRC Richie even wrote a paper on dymanic array allocation in the mid-80ies.

Code is bigger and more complex these days.

//Markus - The panamahat hscker

Skickat ifrån min mobil.
Den 5 apr 2014 15:28 skrev =?ISO-8859-1?Q?Elias_M=E5rtenson?= <address@hidden>:
>
> I read that description too, but they never clarify what those problems may be. The only thing I can think of is the risk of blowing the stack if the block is too large, but that is not different from using dynamically allocated arrays in C like you used to.
>
> Regards,
> Elias
>
>
> On 5 April 2014 21:26, Juergen Sauermann <address@hidden> wrote:
>>
>> Hi,
>>
>> I hope the Solaris issues are fixed now (SVN 187). Please complain if not.
>>
>> I decided against alloca() because the description on its man page
>> suggested more problems than advantages.
>>
>> /// Jürgen
>>
>>
>>
>> On 04/03/2014 02:55 PM, Elias Mårtenson wrote:
>>>
>>> It would, but OpenMP is not supported on it. Also, the Solaris Studio compiler tends to generate better code.
>>>
>>> Also, alloca() (as opposed to malloc()  which allocates memory on the heap) behaves exactly the same as dynamically advocated arrays. They both allocate space on the stack. In fact, I believe GCC generates exactly the same code for both cases. They both essentially translates to an add instruction of the stack pointer.
>>>
>>> Regards,
>>> Elias
>>>
>>> On 3 Apr 2014 20:33, "Juergen Sauermann" <address@hidden> wrote:
>>>>
>>>> Hi Elias,
>>>>
>>>> I will look into this, but some have performance impacts (dynamic arrays).
>>>> Wouldn't it make sense to install gcc on Solaris?
>>>>
>>>> /// Jürgen
>>>>
>>>>
>>>> On 04/02/2014 12:46 PM, Elias Mårtenson wrote:
>>>>>
>>>>> Also, if you want to try out the Solaris compiler, it's available for free for Linux as well: http://www.oracle.com/technetwork/server-storage/solarisstudio/beta-1947596.html
>>>>>
>>>>> To enable OpenMP you need to compile with -xopenmp=parallel and set some environment variables as described here: http://docs.oracle.com/cd/E18659_01/html/821-1381/aewcb.html#gkcrd
>>>>>
>>>>> Regards,
>>>>> Elias
>>>>>
>>>>>
>>>>> On 2 April 2014 18:39, Elias Mårtenson <address@hidden> wrote:
>>>>>>
>>>>>> Oh, and there are a few more dynamically sized arrays:
>>>>>> phrase_gen.cc:115 and 222
>>>>>> Regards,
>>>>>> Elias
>>>>>>
>>>>>>
>>>>>> On 2 April 2014 18:34, Elias Mårtenson <address@hidden> wrote:
>>>>>>>
>>>>>>> On 2 April 2014 18:32, Elias Mårtenson <address@hidden> wrote:
>>>>>>>
>>>>>>>> Declaring an array with a size computed at runtime is not actually allowed (it's supported in modern C, and also supported in C++ as an extension).
>>>>>>>
>>>>>>>
>>>>>>> What I meant was that it's supported in GCC as an extension, not C++.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Elias
>>>>>>
>>>>>>
>>>>>
>>>>
>>
>