Profile perf(3)'s report into YARV instructions

yarv-profile.rb

#!/usr/bin/env ruby
require 'pp'

files = {'vm.inc' => [], 'insns.def' => []}
current_insn = nil
current_filename = 'vm.inc'
lineno_offset = 0
IO.foreach('vm.inc') do |line|
  case line
  when /^INSN_ENTRY\((\w+)\)/
    files[current_filename] << $. - lineno_offset
    current_insn = $1
    files[current_filename] << current_insn
  when /#line (\d+) "([^"]+)"/
    current_filename = $2
    lineno_offset = $. - $1.to_i
    files[current_filename] << $. - lineno_offset
    files[current_filename] << current_insn
  end
end

def find_insn(files, fn, lineno)
  ary = files[fn]
  return nil unless ary
  current = nil
  ary.each_slice(2) do |n, insn|
    return current || insn if lineno < n
    current = insn
  end
end

addrs = {}
s = `perf annotate -svm_exec_core --stdio --no-source`
s.scan(/^ *(?=[.0]*[1-9])([ .0-9]*) :\s*(\h+)/) do |pct, addr|
  h = (addrs[addr.hex] ||= {})
  h[:pct] = pct.to_f
end

/\A0*(\h+)[ .a-z]*\t0*(\h+)/i =~ `objdump -t miniruby|grep vm_exec_core`
#puts"0x#{$1}..#{"%#x"%[$1.hex+$2.hex]}"
from = $1.hex
to = from + $2.hex

`readelf --debug-dump=decodedline miniruby`.
  scan(/^([a-z_.]+)\s+(\d+)\s+0x(\h+)/) do |fn, no, a|
  addr = a.hex
  next if addr < from
  break if addr > to
  lineno = no.to_i
  h = (addrs[addr] ||= {})
  h[:filename] = fn
  h[:lineno] = lineno
  insn = find_insn(files, fn, lineno)
  h[:insn] = insn if insn
end

pcts = {}
current = ""
addrs.each_pair do |addr, h|
  insn = h[:insn]
  current = insn if insn
  next unless pct = h[:pct]
  pcts[current] ||= 0.0
  pcts[current] += pct
end

pcts.sort_by(&:last).reverse_each do |key, pct|
  puts "%20s: %5.2f" % [key, pct]
end