[llvm] [BOLT][heatmap] Produce zoomed-out heatmaps (PR #140153)

[Amir Ayupov via llvm-commits]

aaupov wrote:

> Instead of introducing the new option, can we reuse `--block-size=` and make it accept multiple values or a different format?
> 
> > If rescaling is impossible, no heatmap is produced.
> 
> Without a printed warning? I understand that the size limitation is driven by implementation, but at the very least we should report that there is no expected output.
> 
> Alternatively, use a different option format that encapsulates the limitations. E.g., `--block-size=<initial_size>{:<scale>:<count>}` or `--block-size=<initial_size>{:<scale1>,<scale2>...}`.

Good call. I prefer the latter approach with explicit scales.


https://github.com/llvm/llvm-project/pull/140153