1 files changed, 40 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/bug972961.js b/js/src/jit-test/tests/basic/bug972961.js
new file mode 100644
index 0000000000..10df12cad8
--- /dev/null
+++ b/js/src/jit-test/tests/basic/bug972961.js
@@ -0,0 +1,40 @@
+// Bug 972961 - Test compiler with very long chains of property accesses
+
+// Return true if we can compile a chain of n property accesses,
+// false if we cannot. Throw if compilation fails in an unexpected way.
+function test(n) {
+    print("testing " + n);
+    try {
+        eval('if (false) {' + Array(n).join(("a.")) + 'a}');
+    } catch (exc) {
+        // Expected outcome if the expression is too deeply nested is an InternalError.
+        if (!(exc instanceof InternalError))
+            throw exc;
+        print(exc.message);
+        return false;
+    }
+    print("no exception");
+    return true;
+}
+
+// Find out how long a chain is enough to break the compiler.
+var n = 4, LIMIT = 0x000fffff;
+var lo = 1, hi = 1;
+while (n <= LIMIT && test(n)) {
+    lo = n;
+    n *= 4;
+}
+
+// Using binary search, find a pass/fail boundary (in order to
+// test the edge case).
+if (n <= LIMIT) {
+    hi = n;
+    while (lo !== hi) {
+        var mid = Math.floor((lo + hi) / 2);
+        if (test(mid))
+            lo = mid + 1;
+        else
+            hi = mid;
+    }
+    print((lo - 1) + " attributes should be enough for anyone");
+}