[memprof] Add Version2 of the indexed MemProf format (#89100)
This patch adds Version2 of the indexed MemProf format. The new
format comes with a hash table from CallStackId to actual call stacks
llvm::SmallVector<FrameId>. The rest of the format refers to call
stacks with CallStackId. This "values + references" model effectively
deduplicates call stacks. Without this patch, a large indexed memprof
file of mine shrinks from 4.4GB to 1.6GB, a 64% reduction.
This patch does not make Version2 generally available yet as I am
planning to make a few more changes to the format.
GitOrigin-RevId: 172f6ddfa7662a36e3a41db6bb944f7d72fd0b00
9 files changed
