[ThinLTO][MemProf] Add option to override max ICP with larger number (#171652)
Adds an option -module-summary-max-indirect-edges, and wiring into the
ICP logic that collects promotion candidates from VP metadata, to
support a larger number of promotion candidates for use in building the
ThinLTO summary. Also use this in the MemProf ThinLTO backend handling
where we perform memprof ICP during cloning.
The new option, essentially off by default, can be used to override the
value of -icp-max-prom, which is checked internally in ICP, with a
larger max value when collecting candidates from the VP metadata.
For MemProf in particular, where we synthesize new VP metadata targets
from allocation contexts, which may not be all that frequent, we need to
be able to include a larger set of these targets in the summary in order
to correctly handle indirect calls in the contexts. Otherwise we will
not set up the callsite graph edges correctly.
llvm-project
e3c621c5 - [ThinLTO][MemProf] Add option to override max ICP with larger number (#171652)
