Basic support for tracking smi-only arrays on ia32.

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
diff --git a/src/ia32/ic-ia32.cc b/src/ia32/ic-ia32.cc
index 3c49e60a5920f97256b680d1da89727203c2ec68..56aa5e212157ad1fe47d0953d57a973d4070bec5 100644
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@@ -734,7 +734,7 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
   //  -- edx    : receiver
   //  -- esp[0] : return address
   // -----------------------------------
-  Label slow, fast, array, extra;
+  Label slow, fast, array, extra, not_smi_only;
 
   // Check that the object isn't a smi.
   __ JumpIfSmi(edx, &slow);
@@ -810,6 +810,19 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
   // ecx: key (a smi)
   // edx: receiver
   // edi: FixedArray receiver->elements
+
+  if (FLAG_smi_only_arrays) {
+    // Make sure that the elements are not smi-only

[Sven Panne, 2011/09/16 09:19:32]

Hmmm, we make sure that the elements *are* smi-only, don't we?

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

Done.

+    __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
+    __ CheckFastSmiOnlyElements(ebx, &not_smi_only, Label::kNear);
+  }
+
+  // Non-smis need to call into the runtime if the array is smi only
+  __ JumpIfNotSmi(eax, &slow);

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

I think all these added lines (up to and including "__ bind(&not_smi_only);")
must go inside the if-block. Otherwise, if the flag is false, you'll never reach
the code that updates the write barrier.

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

Done.

+  __ mov(CodeGenerator::FixedArrayElementOperand(edi, ecx), eax);
+  __ ret(0);
+
+  __ bind(&not_smi_only);
   __ mov(CodeGenerator::FixedArrayElementOperand(edi, ecx), eax);
   // Update write barrier for the elements array address.
   __ mov(edx, Operand(eax));