stackcollapse reporting for flamegraphs

bin/stackprof

@@ -17,6 +17,7 @@ parser = OptionParser.new(ARGV) do |o|
   o.on('--sort-total', "Sort --text or --files output on total samples\n\n"){ options[:sort] = true }
   o.on('--method [grep]', 'Zoom into specified method'){ |f| options[:format] = :method; options[:filter] = f }
   o.on('--file [grep]', 'Show annotated code for specified file'){ |f| options[:format] = :file; options[:filter] = f }
+  o.on('--stackcollapse', 'stackcollapse.pl compatible output (use with flamegraph.pl)'){ options[:format] = :stackcollapse }
   o.on('--callgrind', 'Callgrind output (use with kcachegrind, gprof2dot)'){ options[:format] = :callgrind }
   o.on('--graphviz', "Graphviz output (use with dot)\n\n"){ options[:format] = :graphviz }
   o.on('--dump', 'Print marshaled profile dump (combine multiple profiles)'){ options[:format] = :dump }
@@ -48,6 +49,8 @@ when :callgrind
   report.print_callgrind
 when :graphviz
   report.print_graphviz
+when :stackcollapse
+  report.print_stackcollapse
 when :method
   report.print_method(options[:filter])
 when :file

lib/stackprof/report.rb

@@ -67,6 +67,18 @@ def print_dump
       puts Marshal.dump(@data.reject{|k,v| k == :files })
     end
 
+    def print_stackcollapse
+      raise "profile does not include raw samples" unless raw = data[:raw]
+
+      while len = raw.shift
+        frames = raw.slice!(0, len)
+        weight = raw.shift
+
+        print frames.map{ |a| data[:frames][a][:name] }.join(';')
+        puts " #{weight}"
+      end
+    end
+
     def print_graphviz(filter = nil, f = STDOUT)
       if filter
         mark_stack = []