Re: [Lightning] Re: failure with GNU lightning on Mac OS X 10.6.2

[Todd Rovito]

2010/2/23 Ludovic Courtès <address@hidden>:
> Hi,
>
> Todd Rovito <address@hidden> writes:
>
>> This GDB was configured as "x86_64-apple-darwin"...Reading symbols for
>
> [...]
>
>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: KERN_PROTECTION_FAILURE at address: 0x0000000100001100
>> 0x0000000100001100 in codeBuffer ()
>
> Could it be that Darwin clears the execution bit on data segments?
>
> You could try allocating ‘codeBuffer’ like this:
>
>  codeBuffer = mmap (NULL, 1024, PROT_EXEC | PROT_READ | PROT_WRITE,
>                     MAP_PRIVATE | MAP_ANONYMOUS, -1, -1);

Ludo,
  Thanks for the help, I think you got me much closer.  Here is the
code with your changes:

   #include <stdio.h>
     #include <sys/mman.h>
     #include "lightning.h"

     static jit_insn *codeBuffer;

     typedef int (*pifi)(int);    /* Pointer to Int Function of Int */

     int main()
     {
       codeBuffer = mmap (NULL, 1024, PROT_EXEC | PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANON, -1, -1);

       pifi  incr = (pifi) (jit_set_ip(codeBuffer).iptr);
       int   in;

       jit_leaf(1);                     /*      leaf  1             */
       in = jit_arg_i();                /* in = arg_i               */
       jit_getarg_i(JIT_R0, in);        /*      getarg_i R0         */
       jit_addi_i(JIT_RET, JIT_R0, 1);  /*      addi_i   RET, R0, 1 */
       jit_ret();                       /*      ret                 */

       jit_flush_code(codeBuffer, jit_get_ip().ptr);

       /* call the generated code, passing 5 as an argument */
       printf("%d + 1 = %d\n", 5, incr(5));
       return 0;
     }

And here are the results I got in gdb:
gdb incrGNU gdb 6.3.50-20050815 (Apple version gdb-1346) (Fri Sep 18
20:40:51 UTC 2009)
Copyright 2004 Free Software Foundation, Inc.
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This GDB was configured as "x86_64-apple-darwin"...Reading symbols for
shared libraries .. done

(gdb) run
Starting program: /Users/rovitotv/prog/lightning/test/incr
Reading symbols for shared libraries +. done

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0xffffffffffffffff
0x0000000100000bde in main () at incr.c:19
19             jit_leaf(1);                     /*      leaf  1             */
(gdb)


It is still crashing.  I really have no idea what I am doing, but
thank you for the help.