Basic support for tracking smi-only arrays on ia32.

src/ia32/ic-ia32.cc

 // 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 716 matching lines @@
 
 
 void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm,
                                    StrictModeFlag strict_mode) {
   // ----------- S t a t e -------------
   //  -- eax    : value
   //  -- ecx    : key
   //  -- 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);
   // Get the map from the receiver.
   __ mov(edi, FieldOperand(edx, HeapObject::kMapOffset));
   // Check that the receiver does not require access checks.  We need
   // to do this because this generic stub does not perform map checks.
   __ test_b(FieldOperand(edi, Map::kBitFieldOffset),
             1 << Map::kIsAccessCheckNeeded);
   __ j(not_zero, &slow);
@@ skipping 55 matching lines @@
   // address to store into and fall through to fast case.
   __ cmp(ecx, FieldOperand(edx, JSArray::kLengthOffset));  // Compare smis.
   __ j(above_equal, &extra);
 
   // Fast case: Do the store.
   __ bind(&fast);
   // eax: value
   // 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));
   __ RecordWrite(edi, 0, edx, ecx);
   __ ret(0);
 }
 
 
 // The generated code does not accept smi keys.
 // The generated code falls through if both probes miss.
@@ skipping 814 matching lines @@
   Condition cc = *jmp_address == Assembler::kJncShortOpcode
       ? not_zero
       : zero;
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32