summaryrefslogtreecommitdiff
path: root/yjit.rb
blob: 3998e4fda81155e9f78eb5cadd930e1b7a3d86e1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
module YJIT
  if defined?(Disasm)
    def self.disasm(iseq, tty: $stdout && $stdout.tty?)
      iseq = RubyVM::InstructionSequence.of(iseq)

      blocks = YJIT.blocks_for(iseq)
      return if blocks.empty?

      str = String.new
      str << iseq.disasm
      str << "\n"

      # Sort the blocks by increasing addresses
      sorted_blocks = blocks.sort_by(&:address)

      highlight = ->(str) {
        if tty
          "\x1b[1m#{str}\x1b[0m"
        else
          str
        end
      }

      cs = YJIT::Disasm.new
      sorted_blocks.each_with_index do |block, i|
        str << "== BLOCK #{i+1}/#{blocks.length}: #{block.code.length} BYTES, ISEQ RANGE [#{block.iseq_start_index},#{block.iseq_end_index}) ".ljust(80, "=")
        str << "\n"

        comments = comments_for(block.address, block.address + block.code.length)
        comment_idx = 0
        cs.disasm(block.code, block.address).each do |i|
          while (comment = comments[comment_idx]) && comment.address <= i.address
            str << "  ; #{highlight.call(comment.comment)}\n"
            comment_idx += 1
          end

          str << sprintf(
            "  %<address>08x:  %<instruction>s\t%<details>s\n",
            address: i.address,
            instruction: i.mnemonic,
            details: i.op_str
          )
        end
      end

      block_sizes = blocks.map { |block| block.code.length }
      total_bytes = block_sizes.sum
      str << "\n"
      str << "Total code size: #{total_bytes} bytes"
      str << "\n"

      str
    end

    def self.comments_for(start_address, end_address)
      Primitive.comments_for(start_address, end_address)
    end

    def self.graphviz_for(iseq)
      iseq = RubyVM::InstructionSequence.of(iseq)
      cs = YJIT::Disasm.new

      highlight = ->(comment) { "<b>#{comment}</b>" }
      linebreak = "<br align=\"left\"/>\n"

      buff = ''
      blocks = blocks_for(iseq).sort_by(&:id)
      buff << "digraph g {\n"

      # Write the iseq info as a legend
      buff << "  legend [shape=record fontsize=\"30\" fillcolor=\"lightgrey\" style=\"filled\"];\n"
      buff << "  legend [label=\"{ Instruction Disassembly For: | {#{iseq.base_label}@#{iseq.absolute_path}:#{iseq.first_lineno}}}\"];\n"

      # Subgraph contains disassembly
      buff << "  subgraph disasm {\n"
      buff << "  node [shape=record fontname=\"courier\"];\n"
      buff << "  edge [fontname=\"courier\" penwidth=3];\n"
      blocks.each do |block|
        disasm = disasm_block(cs, block, highlight)

        # convert newlines to breaks that graphviz understands
        disasm.gsub!(/\n/, linebreak)

        # strip leading whitespace
        disasm.gsub!(/^\s+/, '')

        buff << "b#{block.id} [label=<#{disasm}>];\n"
        buff << block.outgoing_ids.map { |id|
          next_block = blocks.bsearch { |nb| id <=> nb.id }
          if next_block.address == (block.address + block.code.length)
            "b#{block.id} -> b#{id}[label=\"Fall\"];"
          else
            "b#{block.id} -> b#{id}[label=\"Jump\" style=dashed];"
          end
        }.join("\n")
        buff << "\n"
      end
      buff << "  }"
      buff << "}"
      buff
    end

    def self.disasm_block(cs, block, highlight)
      comments = comments_for(block.address, block.address + block.code.length)
      comment_idx = 0
      str = ''
      cs.disasm(block.code, block.address).each do |i|
        while (comment = comments[comment_idx]) && comment.address <= i.address
          str << "  ; #{highlight.call(comment.comment)}\n"
          comment_idx += 1
        end

        str << sprintf(
          "  %<address>08x:  %<instruction>s\t%<details>s\n",
          address: i.address,
          instruction: i.mnemonic,
          details: i.op_str
        )
      end
      str
    end
  end

  # Return a hash for statistics generated for the --yjit-stats command line option.
  # Return nil when option is not passed or unavailable.
  def self.runtime_stats
    # defined in yjit_iface.c
    Primitive.get_yjit_stats
  end

  # Discard statistics collected for --yjit-stats.
  def self.reset_stats!
    # defined in yjit_iface.c
    Primitive.reset_stats_bang
  end

  class << self
    private

    # Format and print out counters
    def _print_stats
      counters = runtime_stats
      return unless counters

      $stderr.puts("***YJIT: Printing YJIT statistics on exit***")
      $stderr.puts("Number of bindings allocated: %d\n" % counters[:binding_allocations])
      $stderr.puts("Number of locals modified through binding: %d\n" % counters[:binding_set])

      print_counters(counters, prefix: 'send_', prompt: 'method call exit reasons: ')
      print_counters(counters, prefix: 'leave_', prompt: 'leave exit reasons: ')
      print_counters(counters, prefix: 'getivar_', prompt: 'getinstancevariable exit reasons:')
      print_counters(counters, prefix: 'setivar_', prompt: 'setinstancevariable exit reasons:')
      print_counters(counters, prefix: 'oaref_', prompt: 'opt_aref exit reasons: ')
    end

    def print_counters(counters, prefix:, prompt:)
      $stderr.puts(prompt)
      counters = counters.filter { |key, _| key.start_with?(prefix) }
      counters.filter! { |_, value| value != 0 }
      counters.transform_keys! { |key| key.to_s.delete_prefix(prefix) }

      if counters.empty?
        $stderr.puts("    (all relevant counters are zero)")
        return
      end

      counters = counters.to_a
      counters.sort_by! { |(_, counter_value)| counter_value }
      longest_name_length = counters.max_by { |(name, _)| name.length }.first.length
      total = counters.sum { |(_, counter_value)| counter_value }

      counters.reverse_each do |(name, value)|
        percentage = value.fdiv(total) * 100
        $stderr.printf("    %*s %10d (%4.1f%%)\n", longest_name_length, name, value, percentage);
      end
    end
  end
end