Answers for Ludovic Brenta and Georg Bauhaus (Re: ada compiler?)

Answers for Ludovic Brenta and Georg Bauhaus (Re: ada compiler?)

[anon]

1. The best way set "-fstack-check" as a default to install the gcc 
   source tree. And as many language packages as you want to 
   default using "-fstack-check". I would say skip JAVA for now.

2. Check for current GNAT or upgrade to GNU GPL version if needed 

3. Configure gcc system as normal with this extra option added 

  --enable-fstack-check

aka

  ../source/configure --enable-fstack-check <other options> 


4. Build GCC system the normal way as describe in manual or the way 
   you like, may be in stages. 

Note: This way, the complete language packages define in the configure 
'--enable-language="c,ada,..."' will be set to use stack checking. As 
for Java you might want to skip this, since the "-fstack-check" routines 
does slow down the execution and JAVA is slow enough. For languages, 
that you want to use without the "stack-check" rebuild in another 
directory the normal way.

The other way I stated only modifies the 'gnat1' but a lot of people here 
may get upset if I show you those instructions. So, you can skip <part 1> 
from the other post. 

Now, the '-fstack-check' add the following three statements to the start 
of each routine.

;        Assembly (x86)       

	leal -4392(%esp),%eax
	pushl %eax              
	call __gnat_stack_check 


--  or the Ada version
    AX := Stack - 4392 ;    --  Insure routine has at least 4392 stack size
    stack_check ( AX )  ;    --  returns if AX is valid stack location 
                               --  else result in Storage_Error exception

Note: the initial constant 4392 may be a different value on other 
systems. 

The 'Stack_Check' function can be found in 
System.Stack_Checking.Operations.Stack_Check function 
defined in the s-stchop.adb file. 


For GNAT RTS, there are 4 packages, that deal with the stacks.

System.Secondary_Stack           => s-secsta.ad?
System.Stack_Usage               => s-stausa.ad?
System.Stack_Checking            => s-stache.ad?
System.Stack_Checking.Operations => s-stchop.ad? -- core routines

Re: Answers for Ludovic Brenta and Georg Bauhaus (Re: ada compiler?)

[Georg Bauhaus]

anon wrote:
> 1. The best way set "-fstack-check" as a default to install the gcc 
>    source tree.

Since Ludovic maintains GNAT for Debian, we have every reason to
assume he is familiar with how to build GNAT from source.
In fact, he has demonstrated how he works with the GCC sources
at an AdaCore session during FOSDEM 2006.
   Debian related Ada sources are also available from a Monotone
repository hosted by Ada France, in case you want to have a look.


> 3. Configure gcc system as normal with this extra option added 
> 
>   --enable-fstack-check

The question is, should this be done? Why? Why not?