Revision: 2940
Author: [email protected]
Date: Mon Sep 21 00:28:04 2009
Log: Minor changes to the native array construct code

Named a constant and added an assert to get notified when related constants
change.

Removed reloading of the Array function when Array is called as a  
constructor as
the Array function is preserved in edi.

This - unlike r2908 and r2909 - both compiles and passes the tests.
Review URL: http://codereview.chromium.org/209012
http://code.google.com/p/v8/source/detail?r=2940

Modified:
  /branches/bleeding_edge/src/ia32/builtins-ia32.cc

=======================================
--- /branches/bleeding_edge/src/ia32/builtins-ia32.cc   Thu Sep 17 00:58:49  
2009
+++ /branches/bleeding_edge/src/ia32/builtins-ia32.cc   Mon Sep 21 00:28:04  
2009
@@ -740,7 +740,10 @@
    __ mov(FieldOperand(scratch1, Array::kLengthOffset), Immediate(holes));

    // Fill the FixedArray with the hole value. Inline the code if short.
-  if (holes <= 4) {
+  // Reconsider loop unfolding if kPreallocatedArrayElements gets changed.
+  static const int kLoopUnfoldLimit = 4;
+  ASSERT(kPreallocatedArrayElements <= kLoopUnfoldLimit);
+  if (holes <= kLoopUnfoldLimit) {
      // Use a scratch register here to have only one reloc info when  
unfolding
      // the loop.
      __ mov(scratch3, Factory::the_hole_value());
@@ -836,8 +839,7 @@
    __ lea(elements_array, Operand(result, JSArray::kSize));
    __ mov(FieldOperand(result, JSArray::kElementsOffset), elements_array);

-  // Initialize the fixed array and fill it with holes. FixedArray length  
is not
-  // stored as a smi.
+  // Initialize the fixed array. FixedArray length is not stored as a smi.
    // result: JSObject
    // elements_array: elements array
    // elements_array_end: start of next object
@@ -909,7 +911,7 @@
    push_count++;
    __ push(eax);

-  // Check for array construction with zero arguments or one.
+  // Check for array construction with zero arguments.
    __ test(eax, Operand(eax));
    __ j(not_zero, &argc_one_or_more);

@@ -1005,8 +1007,8 @@
    // Location of the last argument
    __ lea(edi, Operand(esp, 2 * kPointerSize));

-  // Location of the first array element (fill_with_holes is false, so the
-  // FixedArray is returned).
+  // Location of the first array element (Parameter fill_with_holes to
+  // AllocateJSArrayis false, so the FixedArray is returned in ecx).
    __ lea(edx, Operand(ecx, FixedArray::kHeaderSize - kHeapObjectTag));

    // ebx: argc
@@ -1068,7 +1070,7 @@
      __ Assert(equal, "Unexpected initial map for Array function");
    }

-  // Run the native code for the Array function called as constructor.
+  // Run the native code for the Array function called as a normal  
function.
    ArrayNativeCode(masm, false, &generic_array_code);

    // Jump to the generic array code in case the specialized code cannot  
handle
@@ -1105,12 +1107,11 @@
    }

    // Run the native code for the Array function called as constructor.
-  ArrayNativeCode(masm, false, &generic_constructor);
+  ArrayNativeCode(masm, true, &generic_constructor);

    // Jump to the generic construct code in case the specialized code cannot
    // handle the construction.
    __ bind(&generic_constructor);
-  GenerateLoadArrayFunction(masm, edi);
    Code* code = Builtins::builtin(Builtins::JSConstructStubGeneric);
    Handle<Code> generic_construct_stub(code);
    __ jmp(generic_construct_stub, RelocInfo::CODE_TARGET);

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