RFC: debugging-GCC commented-out-code architecture

[Bernardo Innocenti]

Chris Lattner wrote:

> You might be interested in how we solved this problem in LLVM.  Basically,
> we have a DEBUG macro that people can wrap their debugging code with, like
> this:
> 
>    ...
>    DEBUG(printf("foo happened!\n"));
>    ...

On AmigaOS, it was common practice to use an equivalent macro called
DB() or even just D().  I find that a shorter name makes it more
attractive.

Another debug facility I've found useful was Microsoft's
ASSERT_VALID_PTR() and ASSERT_VALID_PTR_OR_NULL().  These macros
should attempt to guess wether a pointer is "valid", perhaps
using a machine-specific, conservative check like this:

 /* GCC doesn't accept asm statements in the middle of an
  * expression such as `a ? b : asm("something")'.
  */
 #define ILLEGAL illegal()
 static __inline__ int illegal(void) { asm("illegal"); return 0; }

 #define ASSERT_VALID_PTR(x) ( (((long)(x) > 1024) && \
     TypeOfMem((x))) ? 0 : \
       ( DBPRINTF ("\x07%s, %ld: bad ptr: " #x " = $%p\n", \
         __FILE__, __LINE__, (x)), ILLEGAL ) )

-- 
  // Bernardo Innocenti - Develer S.r.l., R&D dept.
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