Version 3.7.1

src/arm/builtins-arm.cc

Index: src/arm/builtins-arm.cc
===================================================================
--- src/arm/builtins-arm.cc	(revision 9808)
+++ src/arm/builtins-arm.cc	(working copy)
@@ -86,12 +86,6 @@
 }
 
 
-// This constant has the same value as JSArray::kPreallocatedArrayElements and
-// if JSArray::kPreallocatedArrayElements is changed handling of loop unfolding
-// below should be reconsidered.
-static const int kLoopUnfoldLimit = 4;
-
-
 // Allocate an empty JSArray. The allocated array is put into the result
 // register. An elements backing store is allocated with size initial_capacity
 // and filled with the hole values.
@@ -101,9 +95,9 @@
                                  Register scratch1,
                                  Register scratch2,
                                  Register scratch3,
-                                 int initial_capacity,
                                  Label* gc_required) {
-  ASSERT(initial_capacity > 0);
+  const int initial_capacity = JSArray::kPreallocatedArrayElements;
+  STATIC_ASSERT(initial_capacity >= 0);
   // Load the initial map from the array function.
   __ ldr(scratch1, FieldMemOperand(array_function,
                                    JSFunction::kPrototypeOrInitialMapOffset));
@@ -153,12 +147,24 @@
   ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
   __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
 
-  // Fill the FixedArray with the hole value.
+  // Fill the FixedArray with the hole value. Inline the code if short.
+  if (initial_capacity == 0) return;
   ASSERT_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
-  ASSERT(initial_capacity <= kLoopUnfoldLimit);
   __ LoadRoot(scratch3, Heap::kTheHoleValueRootIndex);
-  for (int i = 0; i < initial_capacity; i++) {
+  static const int kLoopUnfoldLimit = 4;
+  if (initial_capacity <= kLoopUnfoldLimit) {
+    for (int i = 0; i < initial_capacity; i++) {
+      __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
+    }
+  } else {
+    Label loop, entry;
+    __ add(scratch2, scratch1, Operand(initial_capacity * kPointerSize));
+    __ b(&entry);
+    __ bind(&loop);
     __ str(scratch3, MemOperand(scratch1, kPointerSize, PostIndex));
+    __ bind(&entry);
+    __ cmp(scratch1, scratch2);
+    __ b(lt, &loop);
   }
 }
 
@@ -173,7 +179,7 @@
 // register elements_array_storage is scratched.
 static void AllocateJSArray(MacroAssembler* masm,
                             Register array_function,  // Array function.
-                            Register array_size,  // As a smi.
+                            Register array_size,  // As a smi, cannot be 0.
                             Register result,
                             Register elements_array_storage,
                             Register elements_array_end,
@@ -181,32 +187,18 @@
                             Register scratch2,
                             bool fill_with_hole,
                             Label* gc_required) {
-  Label not_empty, allocated;
-
   // Load the initial map from the array function.
   __ ldr(elements_array_storage,
          FieldMemOperand(array_function,
                          JSFunction::kPrototypeOrInitialMapOffset));
 
-  // Check whether an empty sized array is requested.
-  __ tst(array_size, array_size);
-  __ b(ne, &not_empty);
+  if (FLAG_debug_code) {  // Assert that array size is not zero.
+    __ tst(array_size, array_size);
+    __ Assert(ne, "array size is unexpectedly 0");
+  }
 
-  // If an empty array is requested allocate a small elements array anyway. This
-  // keeps the code below free of special casing for the empty array.
-  int size = JSArray::kSize +
-             FixedArray::SizeFor(JSArray::kPreallocatedArrayElements);
-  __ AllocateInNewSpace(size,
-                        result,
-                        elements_array_end,
-                        scratch1,
-                        gc_required,
-                        TAG_OBJECT);
-  __ jmp(&allocated);
-
   // Allocate the JSArray object together with space for a FixedArray with the
   // requested number of elements.
-  __ bind(&not_empty);
   STATIC_ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
   __ mov(elements_array_end,
          Operand((JSArray::kSize + FixedArray::kHeaderSize) / kPointerSize));
@@ -226,7 +218,6 @@
   // result: JSObject
   // elements_array_storage: initial map
   // array_size: size of array (smi)
-  __ bind(&allocated);
   __ str(elements_array_storage, FieldMemOperand(result, JSObject::kMapOffset));
   __ LoadRoot(elements_array_storage, Heap::kEmptyFixedArrayRootIndex);
   __ str(elements_array_storage,
@@ -256,14 +247,6 @@
   ASSERT_EQ(0 * kPointerSize, FixedArray::kMapOffset);
   __ str(scratch1, MemOperand(elements_array_storage, kPointerSize, PostIndex));
   STATIC_ASSERT(kSmiTag == 0);
-  __ tst(array_size, array_size);
-  // Length of the FixedArray is the number of pre-allocated elements if
-  // the actual JSArray has length 0 and the size of the JSArray for non-empty
-  // JSArrays. The length of a FixedArray is stored as a smi.
-  __ mov(array_size,
-         Operand(Smi::FromInt(JSArray::kPreallocatedArrayElements)),
-         LeaveCC,
-         eq);
   ASSERT_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
   __ str(array_size,
          MemOperand(elements_array_storage, kPointerSize, PostIndex));
@@ -311,20 +294,20 @@
 static void ArrayNativeCode(MacroAssembler* masm,
                             Label* call_generic_code) {
   Counters* counters = masm->isolate()->counters();
-  Label argc_one_or_more, argc_two_or_more;
+  Label argc_one_or_more, argc_two_or_more, not_empty_array, empty_array;
 
   // Check for array construction with zero arguments or one.
   __ cmp(r0, Operand(0, RelocInfo::NONE));
   __ b(ne, &argc_one_or_more);
 
   // Handle construction of an empty array.
+  __ bind(&empty_array);
   AllocateEmptyJSArray(masm,
                        r1,
                        r2,
                        r3,
                        r4,
                        r5,
-                       JSArray::kPreallocatedArrayElements,
                        call_generic_code);
   __ IncrementCounter(counters->array_function_native(), 1, r3, r4);
   // Setup return value, remove receiver from stack and return.
@@ -339,6 +322,13 @@
   __ b(ne, &argc_two_or_more);
   STATIC_ASSERT(kSmiTag == 0);
   __ ldr(r2, MemOperand(sp));  // Get the argument from the stack.
+  __ tst(r2, r2);
+  __ b(ne, &not_empty_array);
+  __ Drop(1);  // Adjust stack.
+  __ mov(r0, Operand(0));  // Treat this as a call with argc of zero.
+  __ b(&empty_array);
+
+  __ bind(&not_empty_array);
   __ and_(r3, r2, Operand(kIntptrSignBit | kSmiTagMask), SetCC);
   __ b(ne, call_generic_code);
 
@@ -1027,9 +1017,9 @@
     __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
 
     // Set up the roots register.
-    ExternalReference roots_address =
-        ExternalReference::roots_address(masm->isolate());
-    __ mov(r10, Operand(roots_address));
+    ExternalReference roots_array_start =
+        ExternalReference::roots_array_start(masm->isolate());
+    __ mov(r10, Operand(roots_array_start));
 
     // Push the function and the receiver onto the stack.
     __ push(r1);