Add spec for Regexp inline caching

Author: eregon

spec/truffle/regexp/inline_caching_spec.rb

@@ -0,0 +1,93 @@
+# truffleruby_primitives: true
+
+# Copyright (c) 2024 Oracle and/or its affiliates. All rights reserved. This
+# code is released under a tri EPL/GPL/LGPL license. You can use it,
+# redistribute it and/or modify it under the terms of the:
+#
+# Eclipse Public License version 2.0, or
+# GNU General Public License version 2, or
+# GNU Lesser General Public License version 2.1.
+
+require_relative '../../ruby/spec_helper'
+
+guard -> { TruffleRuby.jit? } do # this test needs splitting
+  describe "Inline caching for dynamically-created Regexp works for" do
+    before :each do
+      @performance_warnings, Warning[:performance] = Warning[:performance], true
+    end
+
+    after :each do
+      Warning[:performance] = @performance_warnings
+    end
+
+    it "Regexp.union with 1 argument" do
+      # Check that separate call sites with fixed input does not warn
+      -> {
+        Regexp.union("a")
+        Regexp.union("b")
+        Regexp.union("c")
+        Regexp.union("d")
+        Regexp.union("e")
+        Regexp.union("f")
+        Regexp.union("g")
+        Regexp.union("h")
+        Regexp.union("i")
+        Regexp.union("j")
+      }.should_not complain
+
+      # Check that calling it with many different inputs has the warning.
+      -> {
+        ("a".."z").each do |pattern|
+          Regexp.union(pattern)
+        end
+      }.should complain(/unbounded creation of regexps/)
+    end
+
+    it "Regexp.union with multiple arguments" do
+      # Check that separate call sites with fixed input does not warn
+      -> {
+        Regexp.union("h", "a")
+        Regexp.union("h", "b")
+        Regexp.union("h", "c")
+        Regexp.union("h", "d")
+        Regexp.union("h", "e")
+        Regexp.union("h", "f")
+        Regexp.union("h", "g")
+        Regexp.union("h", "h")
+        Regexp.union("h", "i")
+        Regexp.union("h", "j")
+      }.should_not complain
+
+      # Check that calling it with many different inputs has the warning.
+      -> {
+        ("a".."z").each do |pattern|
+          Regexp.union("h", pattern)
+        end
+      }.should complain(/unbounded creation of regexps/)
+    end
+
+    it "String#scan" do
+      # Check that separate call sites with fixed input does not warn
+      -> {
+        "zzz".scan("a")
+        "zzz".scan("b")
+        "zzz".scan("c")
+        "zzz".scan("d")
+        "zzz".scan("e")
+        "zzz".scan("f")
+        "zzz".scan("g")
+        "zzz".scan("h")
+        "zzz".scan("i")
+        "zzz".scan("j")
+      }.should_not complain
+
+      # Check that calling it with many different inputs has the warning.
+      -> {
+        # "a".."z" and not just "a".."j" because there can be some late heuristic megamorphic splitting by TRegex (ExecCompiledRegexNode)
+        ("a".."z").each do |pattern|
+          "zzz".scan(pattern)
+        end
+      }.should complain(/unbounded creation of regexps/)
+    end
+  end
+end