Add custom typed ICs for pixel array loads.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
===================================================================
--- src/x64/ic-x64.cc	(revision 6456)
+++ src/x64/ic-x64.cc	(working copy)
@@ -767,6 +767,41 @@
 }
 
 
+void KeyedLoadIC::GeneratePixelArray(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rax    : key
+  //  -- rdx    : receiver
+  //  -- rsp[0] : return address
+  // -----------------------------------
+  Label slow;
+
+  // Verify that it's safe to access the receiver's elements.
+  GenerateKeyedLoadReceiverCheck(
+      masm, rdx, rcx, Map::kHasNamedInterceptor, &slow);
+
+  // Verify that the receiver has pixel array elements.
+  __ movq(rcx, FieldOperand(rdx, JSObject::kElementsOffset));
+  __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
+                 Heap::kPixelArrayMapRootIndex);
+  __ j(not_equal, &slow);
+
+  // Check that the key is a smi and in range.
+  __ JumpIfNotSmi(rax, &slow);
+  __ SmiToInteger32(rbx, rax);
+  __ cmpl(rbx, FieldOperand(rcx, PixelArray::kLengthOffset));
+  __ j(above_equal, &slow);
+
+  // Load and tag the element as a smi.
+  __ movq(rax, FieldOperand(rcx, PixelArray::kExternalPointerOffset));
+  __ movzxbq(rax, Operand(rax, rbx, times_1, 0));
+  __ Integer32ToSmi(rax, rax);
+  __ ret(0);
+
+  __ bind(&slow);
+  GenerateMiss(masm);
+}
+
+
 void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax     : value