Basic support for tracking smi-only arrays on ia32.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 82039faebf3bb32188d8ba1058b11d498e1046f2..d418629ea0597b964fd534c44f4f548ddd53330d 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -3929,6 +3929,7 @@ HInstruction* HGraphBuilder::BuildExternalArrayElementAccess(
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
         break;
+      case FAST_SMI_ONLY_ELEMENTS:
       case FAST_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
       case DICTIONARY_ELEMENTS:
@@ -4040,10 +4041,10 @@ HValue* HGraphBuilder::HandlePolymorphicElementAccess(HValue* object,
   HLoadExternalArrayPointer* external_elements = NULL;
   HInstruction* checked_key = NULL;
 
-  // FAST_ELEMENTS is assumed to be the first case.
-  STATIC_ASSERT(FAST_ELEMENTS == 0);
+  // FAST_SMI_ONLY_ELEMENTS is assumed to be the first case.
+  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
 
-  for (ElementsKind elements_kind = FAST_ELEMENTS;
+  for (ElementsKind elements_kind = FAST_SMI_ONLY_ELEMENTS;

[Rico, 2011/09/16 09:40:10]

Use FIRST_ELEMENTS_KIND instead and remove assert? (or am I missing something
subtle here?

[Jakob Kummerow, 2011/09/16 16:30:34]

The point is that fast elements are handled before external elements. You could
express that with a different assert, but some assert is necessary.

[danno, 2011/09/21 14:32:04]

Done.

        elements_kind <= LAST_ELEMENTS_KIND;
        elements_kind = ElementsKind(elements_kind + 1)) {
     // After having handled FAST_ELEMENTS and DICTIONARY_ELEMENTS, we

[Jakob Kummerow, 2011/09/16 16:30:34]

Update this comment please (either "FAST_SMI_ONLY_ELEMENTS, FAST_ELEMENTS and
DICT...", or just "fast elements and DICT..."

[danno, 2011/09/21 14:32:04]

Done.

@@ -4069,11 +4070,13 @@ HValue* HGraphBuilder::HandlePolymorphicElementAccess(HValue* object,
 
       set_current_block(if_true);
       HInstruction* access;
-      if (elements_kind == FAST_ELEMENTS ||
+      if (elements_kind == FAST_SMI_ONLY_ELEMENTS ||
+          elements_kind == FAST_ELEMENTS ||
           elements_kind == FAST_DOUBLE_ELEMENTS) {
         bool fast_double_elements =
             elements_kind == FAST_DOUBLE_ELEMENTS;
-        if (is_store && elements_kind == FAST_ELEMENTS) {
+        if (is_store && (elements_kind == FAST_ELEMENTS ||

[Rico, 2011/09/16 09:40:10]

is_store && !fast_double_elements ?

[danno, 2011/09/21 14:32:04]

Done.

+                         elements_kind == FAST_SMI_ONLY_ELEMENTS)) {
           AddInstruction(new(zone()) HCheckMap(
               elements, isolate()->factory()->fixed_array_map(),
               elements_kind_branch));
@@ -4097,8 +4100,11 @@ HValue* HGraphBuilder::HandlePolymorphicElementAccess(HValue* object,
                                                          checked_key,
                                                          val));
           } else {
+            ASSERT(elements_kind != FAST_SMI_ONLY_ELEMENTS);

[Rico, 2011/09/16 09:40:10]

Why can't we end up here with FAST_SMI_ONLY_ELEMENTS ?

[danno, 2011/09/21 14:32:04]

Done.

             access = AddInstruction(
-                new(zone()) HStoreKeyedFastElement(elements, checked_key, val));
+                new(zone()) HStoreKeyedFastElement(elements,

[Jakob Kummerow, 2011/09/16 16:30:34]

Why the line breaks?

[danno, 2011/09/21 14:32:04]

Done.

+                                                   checked_key,
+                                                   val));
           }
         } else {
           if (fast_double_elements) {