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Diffstat (limited to 'tool/zjit_bisect.rb')
| -rwxr-xr-x | tool/zjit_bisect.rb | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/tool/zjit_bisect.rb b/tool/zjit_bisect.rb new file mode 100755 index 0000000000..a265a3c01f --- /dev/null +++ b/tool/zjit_bisect.rb @@ -0,0 +1,165 @@ +#!/usr/bin/env ruby +require 'logger' +require 'optparse' +require 'shellwords' +require 'tempfile' +require 'timeout' + +required_ruby_version = Gem::Version.new("3.4.0") +raise "Ruby version #{required_ruby_version} or higher is required" if Gem::Version.new(RUBY_VERSION) < required_ruby_version + +ARGS = {timeout: 5} +OptionParser.new do |opts| + opts.banner += " <path_to_ruby> -- <options>" + opts.on("--timeout=TIMEOUT_SEC", "Seconds until child process is killed") do |timeout| + ARGS[:timeout] = Integer(timeout) + end + opts.on("-h", "--help", "Prints this help") do + puts opts + exit + end +end.parse! + +usage = "Usage: zjit_bisect.rb <path_to_ruby> -- <options>" +RUBY = ARGV[0] || raise(usage) +OPTIONS = ARGV[1..] +raise(usage) if OPTIONS.empty? +LOGGER = Logger.new($stdout) + +# From https://github.com/tekknolagi/omegastar +# MIT License +# Copyright (c) 2024 Maxwell Bernstein and Meta Platforms +# Attempt to reduce the `items` argument as much as possible, returning the +# shorter version. `fixed` will always be used as part of the items when +# running `command`. +# `command` should return True if the command succeeded (the failure did not +# reproduce) and False if the command failed (the failure reproduced). +def bisect_impl(command, fixed, items, indent="") + LOGGER.info("#{indent}step fixed[#{fixed.length}] and items[#{items.length}]") + while items.length > 1 + LOGGER.info("#{indent}#{fixed.length + items.length} candidates") + # Return two halves of the given list. For odd-length lists, the second + # half will be larger. + half = items.length / 2 + left = items[0...half] + right = items[half..] + if !command.call(fixed + left) + items = left + next + end + if !command.call(fixed + right) + items = right + next + end + # We need something from both halves to trigger the failure. Try + # holding each half fixed and bisecting the other half to reduce the + # candidates. + new_right = bisect_impl(command, fixed + left, right, indent + "< ") + new_left = bisect_impl(command, fixed + new_right, left, indent + "> ") + return new_left + new_right + end + items +end + +# From https://github.com/tekknolagi/omegastar +# MIT License +# Copyright (c) 2024 Maxwell Bernstein and Meta Platforms +def run_bisect(command, items) + LOGGER.info("Verifying items") + if command.call(items) + raise StandardError.new("Command succeeded with full items") + end + if !command.call([]) + raise StandardError.new("Command failed with empty items") + end + bisect_impl(command, [], items) +end + +def add_zjit_options cmd + if RUBY == "make" + # Automatically detect that we're running a make command instead of a Ruby + # one. Pass the bisection options via RUN_OPTS/SPECOPTS instead. + zjit_opts = cmd.select { |arg| arg.start_with?("--zjit") } + run_opts_index = cmd.find_index { |arg| arg.start_with?("RUN_OPTS=") } + specopts_index = cmd.find_index { |arg| arg.start_with?("SPECOPTS=") } + if run_opts_index && specopts_index + raise "Expected only one of RUN_OPTS or SPECOPTS to be present in make command, but both were found" + end + if run_opts_index + run_opts = Shellwords.split(cmd[run_opts_index].delete_prefix("RUN_OPTS=")) + run_opts.concat(zjit_opts) + cmd[run_opts_index] = "RUN_OPTS=#{run_opts.shelljoin}" + elsif specopts_index + specopts = Shellwords.split(cmd[specopts_index].delete_prefix("SPECOPTS=")) + # SPECOPTS needs -T before each option to pass it through mspec to Ruby + zjit_opts.each { |opt| specopts.concat(["-T", opt]) } + cmd[specopts_index] = "SPECOPTS=#{specopts.shelljoin}" + else + raise "Expected RUN_OPTS or SPECOPTS to be present in make command" + end + cmd = cmd - zjit_opts + end + cmd +end + +def run_ruby *cmd + cmd = add_zjit_options(cmd) + pid = Process.spawn(*cmd, { + in: :close, + out: [File::NULL, File::RDWR], + err: [File::NULL, File::RDWR], + }) + begin + status = Timeout.timeout(ARGS[:timeout]) do + Process::Status.wait(pid) + end + rescue Timeout::Error + Process.kill("KILL", pid) + LOGGER.warn("Timed out after #{ARGS[:timeout]} seconds") + status = Process::Status.wait(pid) + end + + status +end + +def run_with_jit_list(ruby, options, jit_list) + # Make a new temporary file containing the JIT list + Tempfile.create("jit_list") do |temp_file| + temp_file.write(jit_list.join("\n")) + temp_file.flush + temp_file.close + # Run the JIT with the temporary file + run_ruby ruby, "--zjit-allowed-iseqs=#{temp_file.path}", *options + end +end + +# Try running with no JIT list to get a stable baseline +unless run_with_jit_list(RUBY, OPTIONS, []).success? + cmd = add_zjit_options([RUBY, "--zjit-allowed-iseqs=/dev/null", *OPTIONS]).shelljoin + raise "The command failed unexpectedly with an empty JIT list. To reproduce, try running the following: `#{cmd}`" +end +# Collect the JIT list from the failing Ruby process +jit_list = nil +Tempfile.create "jit_list" do |temp_file| + run_ruby RUBY, "--zjit-log-compiled-iseqs=#{temp_file.path}", *OPTIONS + jit_list = File.readlines(temp_file.path).map(&:strip).reject(&:empty?) +end +LOGGER.info("Starting with JIT list of #{jit_list.length} items.") +# Try running without the optimizer +status = run_with_jit_list(RUBY, ["--zjit-disable-hir-opt", *OPTIONS], jit_list) +if status.success? + LOGGER.warn "*** Command suceeded with HIR optimizer disabled. HIR optimizer is probably at fault. ***" +end +# Now narrow it down +command = lambda do |items| + run_with_jit_list(RUBY, OPTIONS, items).success? +end +result = run_bisect(command, jit_list) +File.open("jitlist.txt", "w") do |file| + file.puts(result) +end +puts "Run:" +jitlist_path = File.expand_path("jitlist.txt") +puts add_zjit_options([RUBY, "--zjit-allowed-iseqs=#{jitlist_path}", *OPTIONS]).shelljoin +puts "Reduced JIT list (available in jitlist.txt):" +puts result |