Re: [RFC - Python scripting] New methods Symtab.global_block and Symtab.static_block (docs included)

[Siva Chandra <sivachandra@google.com>]

Thank Phil, for taking a look.  Comments below.

Phil> We already have gdb.Block.is_static and gdb.Block.is_global.  I don't
Phil> have an objection to this patch per-se, but wouldn't the user acquire
Phil> the global/static blocks similarly by iterating the blocks in the
Phil> Python code and doing the above tests?

Is there a way to iterate over all blocks of a Symtab right after
loading?  If yes, my mistake for having missed it, and this patch is
not necessary.  The idea behind most of the patches I am sending is to
have an exploratory path Objfile => Symtab => Block => Symbol.  This
part addresses Symtab => Block part but not completely; good enough
for my immediate needs though.

Phil> I don't think GNU Style ChangeLogs allow for a summary line.  I don't
Phil> have an issue with it, but, check with maintainers.  Just a nit.

There many examples in ChangeLog with a summary line.  There are of
course many others without :-)

>> +static PyObject *
>> +stpy_global_block (PyObject *self, PyObject *args)
>> +{
>> +  struct symtab *symtab = NULL;
>> > +  struct block *block = NULL;
>> +
>> +  STPY_REQUIRE_VALID (self, symtab);
>> +
>> +  block = symtab->blockvector->block[GLOBAL_BLOCK];
>> +  return block_to_block_object (block, symtab->objfile);

Phil> I don't think so, but can block ever be NULL here?  Looking at the
Phil> code, I'm not even sure if it would matter as set_block just stores a
Phil> reference to the passed block.  However, blpy_get_superblock has a
Phil> NULL block check, so it might be worthwhile checking it out.

As I understand, blpy_get_superblock has a check, as the top most
block will not have a superblock.  In which case, returning None is
probably more appropriate (as it is a logically valid situation) than
returning a NULL.  However, in the case of this patch, is there a
chance that a symtab->blockvector->nblocks == 0?  Similarly, is there
a chance blockvector->nblocks > 0 but blockvector->block[GLOBAL_BLOCK]
(or blockvector->block[STATIC_BLOCK]) is NULL for a logical valid
situation?

Thanks,
Siva Chandra