1 files changed, 67 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Script-getEffectfulOffsets.js b/js/src/jit-test/tests/debug/Script-getEffectfulOffsets.js
new file mode 100644
index 0000000000..2221b7e6cd
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Script-getEffectfulOffsets.js
@@ -0,0 +1,67 @@
+// Check that Script.getEffectfulOffsets behaves sensibly.
+
+var g = newGlobal({newCompartment: true});
+var dbg = Debugger(g);
+var numEffectfulOperations;
+
+function onNewScript(script) {
+  script.getChildScripts().forEach(onNewScript);
+  numEffectfulOperations += script.getEffectfulOffsets().length;
+}
+dbg.onNewScript = onNewScript;
+
+function test(code, expected) {
+  numEffectfulOperations = 0;
+  g.eval(`
+function f(a, b, c) {
+${code}
+}
+`);
+  assertEq(numEffectfulOperations, expected);
+}
+
+const base = 1;
+test("", base);
+
+test("a.f = 0", base + 1);
+test("a.f++", base + 1);
+test("return a.f", base + 0);
+test("a[b] = 0", base + 1);
+test("a[b]++", base + 1);
+test("return a[b]", base + 0);
+test("a = 0", base + 0);
+test("d = 0", base + 1);
+test("with (a) { b = 0; }", base + 7);
+test("let o = {}; ({x: o.x} = { x: 10 })", base + 1);
+test("var x", base + 0);
+
+// d is not closed over, and "let d = 0;" uses InitLexical,
+// which is non-effectful.
+test(`
+let d = 10;
+`, base + 0);
+
+// d is closed over, and "let d = 0;" uses InitAliasedLexical with hops == 0,
+// which is non-effectful.
+test(`
+let d = 10;
+function g() {
+  d;
+}
+`, base + 0);
+
+// Private accessor uses InitAliasedLexical with hops == 1,
+// which is currently marked as effectful.
+// Please fix this test if it's marked as non-effectful in the future.
+test(`
+class B {
+  set #x(x) {}
+}
+`, base + 1);
+
+test(`
+class B {
+  get #x() {}
+  set #x(x) {}
+}
+`, base + 2);