Re: [PATCH] Remove a call to blockvector::map

[Kevin Buettner <kevinb@redhat.com>]

On Wed, 19 Nov 2025 14:45:59 -0700
Tom Tromey <tom@tromey.com> wrote:

> block_starting_point_at checks blockvector::map before doing a lookup.
> 
> This patch removes this call, a step toward making the blockvector API
> a bit more opaque.  It arranges to find the necessary blockvector just
> once, in gather_inline_frames, and then uses the 'lookup' method to
> find the desired block.
> 
> Note that this is a slight change of semantics, in that the old code
> looked only in the map while the new code looks in the blockvector,
> regardless of whether a map was made.  However, I don't think this
> should matter, and furthermore this seems like an abstraction
> violation, with the inline-frame code knowing details of how buildsym
> decided to create the blockvector.
> 
> in the longer run, I think only the 'lookup' method should be provided
> by blockvector -- that is, separately checking the map should be
> impossible.  The idea here is that eventually, for lazy CU expansion,
> we will want to be able to expand the blockvector.  This may be easier
> with a different underlying data structure, so perhaps the map will go
> away entirely.  After this patch, one such use remains.
> 
> Regression tested on x86-64 Fedora 40.

LGTM.

Approved-by: Kevin Buettner <kevinb@redhat.com>