Prefer th->ec for stack base/size. (#13101)

Merged-By: ioquatix <samuel@codeotaku.com>

test/-ext-/stack/test_stack_overflow.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+require 'test/unit'
+
+class Test_StackOverflow < Test::Unit::TestCase
+  def test_proc_overflow
+    omit("Windows stack overflow handling is missing") if RUBY_PLATFORM =~ /mswin|win32|mingw/
+
+    assert_separately([], <<~RUBY)
+      # GC may try to scan the top of the stack and cause a SEGV.
+      GC.disable
+      require '-test-/stack'
+
+      assert_raise(SystemStackError) do
+        Thread.alloca_overflow
+      end
+    RUBY
+  end
+
+  def test_thread_stack_overflow
+    omit("Windows stack overflow handling is missing") if RUBY_PLATFORM =~ /mswin|win32|mingw/
+
+    assert_separately([], <<~RUBY)
+      require '-test-/stack'
+      GC.disable
+
+      thread = Thread.new do
+        Thread.current.report_on_exception = false
+        Thread.alloca_overflow
+      end
+
+      assert_raise(SystemStackError) do
+        thread.join
+      end
+    RUBY
+  end
+
+  def test_fiber_stack_overflow
+    omit("Windows stack overflow handling is missing") if RUBY_PLATFORM =~ /mswin|win32|mingw/
+
+    assert_separately([], <<~RUBY)
+      require '-test-/stack'
+      GC.disable
+
+      fiber = Fiber.new do
+        Thread.alloca_overflow
+      end
+
+      assert_raise(SystemStackError) do
+        fiber.resume
+      end
+    RUBY
+  end
+end