Add benchmarks.rb

`bundle exec ruby benchmarks.rb core/**/*.rbs`

Author: soutaro

benchmarks.rb

@@ -0,0 +1,34 @@
+require "rbs"
+require "benchmark/ips"
+require "csv"
+
+results = []
+
+ARGV.each do |file|
+  GC.start
+  
+  STDERR.puts "Benchmarking with #{file}..."
+  content = File.read(file)
+
+  benchmark = Benchmark.ips do |x|
+    x.report(file) do
+      RBS::Parser.parse_signature(content)
+    end
+
+    x.quiet = true
+  end
+
+  results << {
+    file: file,
+    size: content.bytesize,
+    ips: benchmark.entries[0].ips,
+    sd: benchmark.entries[0].ips_sd
+  }
+end
+
+puts CSV.generate {|csv|
+  csv << ["File", "Size", "IPS", "SD"]
+  results.each do |result|
+    csv << [result[:file], result[:size], result[:ips], result[:sd]]
+  end
+}