Revert "Second attempt at introducing a premonomorphic state in the call"

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 501b5c7dffab1af6439ff9c66f9407ffe612ba09..b3a3acf3e76a36a2eccdf9aaaca9958fdbbce0e8 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -3012,17 +3012,12 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   // r1 : the function to call
   // r2 : Feedback vector
   // r3 : slot in feedback vector (Smi)
-  Label check_array, initialize_array, initialize_non_array, megamorphic, done;
+  Label initialize, done, miss, megamorphic, not_array_function;
 
   ASSERT_EQ(*TypeFeedbackInfo::MegamorphicSentinel(masm->isolate()),
             masm->isolate()->heap()->undefined_value());
-  Heap::RootListIndex kMegamorphicRootIndex = Heap::kUndefinedValueRootIndex;
   ASSERT_EQ(*TypeFeedbackInfo::UninitializedSentinel(masm->isolate()),
             masm->isolate()->heap()->the_hole_value());
-  Heap::RootListIndex kUninitializedRootIndex = Heap::kTheHoleValueRootIndex;
-  ASSERT_EQ(*TypeFeedbackInfo::PremonomorphicSentinel(masm->isolate()),
-            masm->isolate()->heap()->null_value());
-  Heap::RootListIndex kPremonomorphicRootIndex = Heap::kNullValueRootIndex;
 
   // Load the cache state into r4.
   __ add(r4, r2, Operand::PointerOffsetFromSmiKey(r3));
@@ -3032,50 +3027,45 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   // function without changing the state.
   __ cmp(r4, r1);
   __ b(eq, &done);
-  __ CompareRoot(r4, kMegamorphicRootIndex);
-  __ b(eq, &done);
 
-  // Check if we're dealing with the Array function or not.
-  __ LoadArrayFunction(r5);
-  __ cmp(r1, r5);
-  __ b(eq, &check_array);
+  // If we came here, we need to see if we are the array function.
+  // If we didn't have a matching function, and we didn't find the megamorph
+  // sentinel, then we have in the slot either some other function or an
+  // AllocationSite. Do a map check on the object in ecx.
+  __ ldr(r5, FieldMemOperand(r4, 0));
+  __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);
+  __ b(ne, &miss);
 
-  // Non-array cache: Check the cache state.
-  __ CompareRoot(r4, kPremonomorphicRootIndex);
-  __ b(eq, &initialize_non_array);
-  __ CompareRoot(r4, kUninitializedRootIndex);
+  // Make sure the function is the Array() function
+  __ LoadArrayFunction(r4);
+  __ cmp(r1, r4);
   __ b(ne, &megamorphic);
-
-  // Non-array cache: Uninitialized -> premonomorphic. The sentinel is an
-  // immortal immovable object (null) so no write-barrier is needed.
-  __ add(r4, r2, Operand::PointerOffsetFromSmiKey(r3));
-  __ LoadRoot(ip, kPremonomorphicRootIndex);
-  __ str(ip, FieldMemOperand(r4, FixedArray::kHeaderSize));
   __ jmp(&done);
 
-  // Array cache: Check the cache state to see if we're in a monomorphic
-  // state where the state object is an AllocationSite object.
-  __ bind(&check_array);
-  __ ldr(r5, FieldMemOperand(r4, 0));
-  __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);
-  __ b(eq, &done);
-
-  // Array cache: Uninitialized or premonomorphic -> monomorphic.
-  __ CompareRoot(r4, kUninitializedRootIndex);
-  __ b(eq, &initialize_array);
-  __ CompareRoot(r4, kPremonomorphicRootIndex);
-  __ b(eq, &initialize_array);
+  __ bind(&miss);
 
-  // Both caches: Monomorphic -> megamorphic. The sentinel is an
-  // immortal immovable object (undefined) so no write-barrier is needed.
+  // A monomorphic miss (i.e, here the cache is not uninitialized) goes
+  // megamorphic.
+  __ CompareRoot(r4, Heap::kTheHoleValueRootIndex);
+  __ b(eq, &initialize);
+  // MegamorphicSentinel is an immortal immovable object (undefined) so no
+  // write-barrier is needed.
   __ bind(&megamorphic);
   __ add(r4, r2, Operand::PointerOffsetFromSmiKey(r3));
-  __ LoadRoot(ip, kMegamorphicRootIndex);
+  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ str(ip, FieldMemOperand(r4, FixedArray::kHeaderSize));
   __ jmp(&done);
 
-  // Array cache: Uninitialized or premonomorphic -> monomorphic.
-  __ bind(&initialize_array);
+  // An uninitialized cache is patched with the function or sentinel to
+  // indicate the ElementsKind if function is the Array constructor.
+  __ bind(&initialize);
+  // Make sure the function is the Array() function
+  __ LoadArrayFunction(r4);
+  __ cmp(r1, r4);
+  __ b(ne, &not_array_function);
+
+  // The target function is the Array constructor,
+  // Create an AllocationSite if we don't already have it, store it in the slot.
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
 
@@ -3091,8 +3081,8 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   }
   __ b(&done);
 
-  // Non-array cache: Premonomorphic -> monomorphic.
-  __ bind(&initialize_non_array);
+  __ bind(&not_array_function);
+
   __ add(r4, r2, Operand::PointerOffsetFromSmiKey(r3));
   __ add(r4, r4, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
   __ str(r1, MemOperand(r4, 0));