Basic support for tracking smi-only arrays on ia32.

test/mjsunit/element-kind.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (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: --allow-natives-syntax
 // Test element kind of objects
 
+support_smi_only_arrays = %HasFastSmiOnlyElements([]);
+
 var element_kind = {
+  fast_smi_only_elements            :  0,
   fast_elements                     :  1,
   fast_double_elements              :  2,
   dictionary_elements               :  3,
   external_byte_elements            :  4,
   external_unsigned_byte_elements   :  5,
   external_short_elements           :  6,
   external_unsigned_short_elements  :  7,
   external_int_elements             :  8,
   external_unsigned_int_elements    :  9,
   external_float_elements           : 10,
   external_double_elements          : 11,
   external_pixel_elements           : 12
 }
 
 // We expect an object to only be of one element kind.
 function assertKind(expected, obj){
-  assertEquals(expected == element_kind.fast_elements,
-               %HasFastElements(obj));
+  if (support_smi_only_arrays) {
+    assertEquals(expected == element_kind.fast_smi_only_elements,
+                 %HasFastSmiOnlyElements(obj));
+    assertEquals(expected == element_kind.fast_elements,
+                 %HasFastElements(obj));
+  } else {
+    assertEquals(expected == element_kind.fast_elements ||
+                 expected == element_kind.fast_smi_only_elements,
+                 %HasFastElements(obj));
+  }
   assertEquals(expected == element_kind.fast_double_elements,
                %HasFastDoubleElements(obj));
   assertEquals(expected == element_kind.dictionary_elements,
                %HasDictionaryElements(obj));
   assertEquals(expected == element_kind.external_byte_elements,
                %HasExternalByteElements(obj));
   assertEquals(expected == element_kind.external_unsigned_byte_elements,
                %HasExternalUnsignedByteElements(obj));
   assertEquals(expected == element_kind.external_short_elements,
                %HasExternalShortElements(obj));
@@ skipping 13 matching lines @@
   assertEquals(expected >= element_kind.external_byte_elements,
                %HasExternalArrayElements(obj));
 }
 
 var me = {};
 assertKind(element_kind.fast_elements, me);
 me.dance = 0xD15C0;
 me.drink = 0xC0C0A;
 assertKind(element_kind.fast_elements, me);
 
+var too = [1,2,3];
+assertKind(element_kind.fast_smi_only_elements, too);
+too.dance = 0xD15C0;
+too.drink = 0xC0C0A;
+assertKind(element_kind.fast_smi_only_elements, too);
+
+// Make sure the element kind transitions from smionly when a non-smi is stored.
 var you = new Array();
+assertKind(element_kind.fast_smi_only_elements, you);
 for(i = 0; i < 1337; i++) {
-  you[i] = i;
+  var val = i;
+  if (i == 1336) {
+    assertKind(element_kind.fast_smi_only_elements, you);
+    val = new Object();
+  }
+  you[i] = val;
 }
 assertKind(element_kind.fast_elements, you);
 
 assertKind(element_kind.dictionary_elements, new Array(0xC0C0A));
 
 // fast_double_elements not yet available
 
 
 assertKind(element_kind.external_byte_elements,           new Int8Array(9001));
 assertKind(element_kind.external_unsigned_byte_elements,  new Uint8Array(007));
 assertKind(element_kind.external_short_elements,          new Int16Array(666));
 assertKind(element_kind.external_unsigned_short_elements, new Uint16Array(42));
 assertKind(element_kind.external_int_elements,            new Int32Array(0xF));
 assertKind(element_kind.external_unsigned_int_elements,   new Uint32Array(23));
 assertKind(element_kind.external_float_elements,          new Float32Array(7));
 assertKind(element_kind.external_double_elements,         new Float64Array(0));
 assertKind(element_kind.external_pixel_elements,          new PixelArray(512));