Re: [PATCH 3/7] [gdbsupport] Factor out base_next_iterator

[Tom de Vries <tdevries@suse.de>]

On 4/30/26 9:09 PM, Simon Marchi wrote:
> On 4/30/26 12:24 PM, Simon Marchi wrote:
>> Rather than copy paste what I mean here, I pushed what I think it could
>> look like to the users/simark/next-iterator branch.
>>
>> https://sourceware.org/git/?p=binutils-gdb.git;a=shortlog;h=refs/heads/users/simark/next-iterator
>> https://sourceware.org/cgit/binutils-gdb/log/?h=users/simark/next-iterator
>>
>> But just to illustrate here is how the function block iterator and
>> range are implemented:
>>
>>    /* Iterator and range type to iterate over this block and its superblocks
>>       within a function.  */
>>
>>    struct function_block_incrementer
>>    {
>>      const block *operator() (const block &b) const noexcept
>>      {
>>        /* If the current item is the function-defining block, we're done.  */
>>        if (b.function () != nullptr)
>> 	return nullptr;
>>
>>        return b.superblock ();
>>      }
>>    };
>>
>>    using function_block_iterator
>>      = base_next_iterator<const block, function_block_incrementer>;
>>    using function_block_range = iterator_range<function_block_iterator>;
> 
> Just a note: in your version, if you pass a global or static block to
> function_block_iterator, it sets the item to nullptr right away, so you
> iterate on nothing.  I couldn't do that in my version, so I chose to
> assert that the block isn't global or static, which puts the
> responsibillity on the caller not to call this on a global or static
> block.  The only caller is in ada-lang.c, it passes the result of
> get_frame_block().  I guess that a block from a frame is always in a
> function (is not the global or static block), but if that assumption
> isn't true, then a check would be needed in the caller.

I think letting the iterator sort this out is the better option.

Thanks,
- Tom