Short-circuit embedded cons strings.

test/mjsunit/regress/regress-embedded-cons-string.js

Index: test/mjsunit/regress/regress-embedded-cons-string.js
diff --git a/test/mjsunit/parallel-invalidate-transition-map.js b/test/mjsunit/regress/regress-embedded-cons-string.js
similarity index 73%
copy from test/mjsunit/parallel-invalidate-transition-map.js
copy to test/mjsunit/regress/regress-embedded-cons-string.js
index 2a2276f1e238bb1c19efe07ff50262d0e983fae6..afb3835688565986e45452d038866025ae11b0f0 100644
--- a/test/mjsunit/parallel-invalidate-transition-map.js
+++ b/test/mjsunit/regress/regress-embedded-cons-string.js
@@ -25,8 +25,9 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --track-fields --track-double-fields --allow-natives-syntax
-// Flags: --parallel-recompilation --parallel-recompilation-delay=50
+// Flags: --fold-constants --nodead-code-elimination
+// Flags: --expose-gc --allow-natives-syntax
+// Flags: --parallel-recompilation --parallel-recompilation-delay=300
 
 if (!%IsParallelRecompilationSupported()) {
   print("Parallel recompilation is disabled. Skipping this test.");
@@ -37,25 +38,29 @@ function assertUnoptimized(fun) {
   assertTrue(%GetOptimizationStatus(fun) != 1);
 }
 
-function new_object() {
-  var o = {};
-  o.a = 1;
-  o.b = 2;
-  return o;
+function test(fun) {
+  fun();
+  fun();
+  %OptimizeFunctionOnNextCall(fun, "parallel");
+  fun();  // Trigger optimization in the background.
+  gc();   // Tenure cons string.
+  assertUnoptimized(fun);      // Compilation not complete yet.
+  %CompleteOptimization(fun);  // Compilation embeds tenured cons string.
+  gc();   // Visit embedded cons string during mark compact.
 }
 
-function add_field(obj) {
-  obj.c = 3;
+function f() {
+  return "abcdefghijklmn" + "123456789";
 }
 
-add_field(new_object());
-add_field(new_object());
-%OptimizeFunctionOnNextCall(add_field, "parallel");
+function g() {
+  return "abcdefghijklmn\u2603" + "123456789";
+}
 
-var o = new_object();
-add_field(o);                      // Trigger optimization.
-assertUnoptimized(add_field);      // Not yet optimized.
-o.c = 2.2;                         // Invalidate transition map.
-%CompleteOptimization(add_field);  // Conclude optimization with...
-assertUnoptimized(add_field);      // ... bailing out due to map dependency.
+function h() {
+  return "abcdefghijklmn\u2603" + "123456789\u2604";
+}
 
+test(f);
+test(g);
+test(h);