mjit_worker.c: support MJIT in forked Ruby process

by launching MJIT worker thread in child Ruby process.

See the comment before `mjit_child_after_fork` for details.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65785 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 38 insertions, 2 deletions

diff --git a/test/ruby/test_jit.rb b/test/ruby/test_jit.rb
index 451ed91a56..b25a9b15a2 100644
--- a/test/ruby/test_jit.rb
+++ b/test/ruby/test_jit.rb
@@ -567,7 +567,7 @@ class TestJIT < Test::Unit::TestCase
     assert_match(/^Successful MJIT finish$/, err)
   end
 
-  def test_unload_units
+  def test_unload_units_and_compaction
     Dir.mktmpdir("jit_test_unload_units_") do |dir|
       # MIN_CACHE_SIZE is 10
       out, err = eval_with_jit({"TMPDIR"=>dir}, "#{<<~"begin;"}\n#{<<~'end;'}", verbose: 1, min_calls: 1, max_cache: 10)
@@ -582,6 +582,12 @@ class TestJIT < Test::Unit::TestCase
           EOS
           i += 1
         end
+
+        if defined?(fork)
+          # test the child does not try to delete files which are deleted by parent,
+          # and test possible deadlock on fork during MJIT unload and JIT compaction on child
+          Process.waitpid(Process.fork {})
+        end
       end;
 
       debug_info = "stdout:\n```\n#{out}\n```\n\nstderr:\n```\n#{err}```\n"
@@ -598,7 +604,7 @@ class TestJIT < Test::Unit::TestCase
       # On --jit-wait, when the number of JIT-ed code reaches --jit-max-cache,
       # it should trigger compaction.
       unless RUBY_PLATFORM.match?(/mswin|mingw/) # compaction is not supported on Windows yet
-        assert_equal(2, compactions.size, debug_info)
+        assert_equal(3, compactions.size, debug_info)
       end
 
       if appveyor_mswin?
@@ -838,6 +844,36 @@ class TestJIT < Test::Unit::TestCase
     assert_equal("-e:8:in `a'\n", lines[1])
   end
 
+  def test_fork_with_mjit_worker_thread
+    Dir.mktmpdir("jit_test_fork_with_mjit_worker_thread_") do |dir|
+      # min_calls: 2 to skip fork block
+      out, err = eval_with_jit({ "TMPDIR" => dir }, "#{<<~"begin;"}\n#{<<~"end;"}", min_calls: 2, verbose: 1)
+      begin;
+        def before_fork; end
+        def after_fork; end
+
+        before_fork; before_fork # the child should not delete this .o file
+        pid = Process.fork do # this child should not delete shared .pch file
+          after_fork; after_fork # this child does not share JIT-ed after_fork with parent
+        end
+        after_fork; after_fork # this parent does not share JIT-ed after_fork with child
+
+        Process.waitpid(pid)
+      end;
+      success_count = err.scan(/^#{JIT_SUCCESS_PREFIX}:/).size
+      assert_equal(3, success_count)
+
+      # assert no remove error
+      lines = err.lines
+      assert_match(/^Successful MJIT finish$/, lines[3])
+      assert_match(/^Successful MJIT finish$/, lines[4])
+
+      # ensure objects are deleted
+      debug_info = "stdout:\n```\n#{out}\n```\n\nstderr:\n```\n#{err}```\n"
+      assert_send([Dir, :empty?, dir], debug_info)
+    end
+  end if defined?(fork)
+
   private
 
   def appveyor_mswin?