Basic support for tracking smi-only arrays on ia32.

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 519210c0dc92376ba3e0c5b8629c8c613442edad..405ae516dcc2d8339a485f50acf34990bf45c8c7 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -374,13 +374,38 @@ void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
 void MacroAssembler::CheckFastElements(Register map,
                                        Label* fail,
                                        Label::Distance distance) {
-  STATIC_ASSERT(FAST_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_ELEMENTS == 1);
   cmpb(FieldOperand(map, Map::kBitField2Offset),
        Map::kMaximumBitField2FastElementValue);
   j(above, fail, distance);
 }
 
 
+void MacroAssembler::CheckFastObjectElements(Register map,
+                                             Label* fail,
+                                             Label::Distance distance) {
+  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_ELEMENTS == 1);
+  cmpb(FieldOperand(map, Map::kBitField2Offset),

[Sven Panne, 2011/09/22 07:43:25]

Perhaps use a load/sub/cmp instead? I am not really sure if this better, but
this would only involve a single mem access.

[danno, 2011/09/22 11:23:15]

The byte load would require a scratch of eax or ebx, and I'd like to avoid
having to have that restriction unless we measure this as a bottleneck.
On 2011/09/22 07:43:25, Sven wrote:

+       Map::kMaximumBitField2FastSmiOnlyElementValue);
+  j(below_equal, fail, distance);
+  cmpb(FieldOperand(map, Map::kBitField2Offset),
+       Map::kMaximumBitField2FastElementValue);
+  j(above, fail, distance);
+}
+
+
+void MacroAssembler::CheckFastSmiOnlyElements(Register map,
+                                              Label* fail,
+                                              Label::Distance distance) {
+  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
+  cmpb(FieldOperand(map, Map::kBitField2Offset),
+       Map::kMaximumBitField2FastSmiOnlyElementValue);
+  j(above, fail, distance);
+}
+
+
 void MacroAssembler::CheckMap(Register obj,
                               Handle<Map> map,
                               Label* fail,