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

[Simon Marchi <simark@simark.ca>]

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.

Simon