Add a "collapse functions matching search filter" transform

[mstange]

Here's a profile in which I've wanted to collapse all region manipulation functions into one node: https://perfht.ml/2FAbwMd

All these functions match the search filter "region32". It would be great if I could collapse based on the function name.

┆Issue is synchronized with this Jira Task

[gregtatum]

Using the "collapse" operation, a stack like so:

A -> region32B -> region32C -> D -> region32E -> region32F -> G

Collapsing on "region32", would collapse to:

A -> search "region32" -> D -> search "region32" -> G

Is this what you were thinking?

[mstange]

Yes, that's what I was thinking! Then I can choose "Collapse function's subtree across the entire tree" on one of the search "region32" nodes and have exactly what I want.

And Boris can collapse JS stuff (or at least an approximation of it) by searching for "js::" and collapsing that.

[gregtatum]

Ahhh... that's a really good point, and proves this is a nicely general transform. We should prioritize it.

[chrisheib]

Has there been work done on this yet? I am struggling with something similar in https://github.com/mstange/samply/issues/639