Fix fast array literals to ignore prototype chain.

This makes sure that boilerplate objects for array literals with
non-constant elements (which will contain the hole at non-constant
positions) will not cause prototype chain lookups when generating
optimized code.

R=erik.corry@gmail.com
BUG=chromium:123512
TEST=mjsunit/regress/regress-123512

Review URL: https://chromiumcodereview.appspot.com/10105025

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11350 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-codegen-arm.cc

@@ -4659,9 +4659,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
         __ str(r2, FieldMemOperand(result, total_offset + 4));
       }
     } else if (elements->IsFixedArray()) {
+      Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       for (int i = 0; i < elements_length; i++) {
         int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
-        Handle<Object> value = JSObject::GetElement(object, i);
+        Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
           __ add(r2, result, Operand(*offset));

src/hydrogen.cc

@@ -3749,10 +3749,11 @@ static bool IsFastLiteral(Handle<JSObject> boilerplate,
     if (boilerplate->HasFastDoubleElements()) {
       *total_size += FixedDoubleArray::SizeFor(elements->length());
     } else if (boilerplate->HasFastElements()) {
+      Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       int length = elements->length();
       for (int i = 0; i < length; i++) {
         if ((*max_properties)-- == 0) return false;
-        Handle<Object> value = JSObject::GetElement(boilerplate, i);
+        Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
           if (!IsFastLiteral(value_object,

src/ia32/lithium-codegen-ia32.cc

@@ -4514,9 +4514,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
         __ mov(FieldOperand(result, total_offset + 4), Immediate(value_high));
       }
     } else if (elements->IsFixedArray()) {
+      Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       for (int i = 0; i < elements_length; i++) {
         int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
-        Handle<Object> value = JSObject::GetElement(object, i);
+        Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
           __ lea(ecx, Operand(result, *offset));

src/mips/lithium-codegen-mips.cc

@@ -4555,9 +4555,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
         __ sw(a2, FieldMemOperand(result, total_offset + 4));
       }
     } else if (elements->IsFixedArray()) {
+      Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       for (int i = 0; i < elements_length; i++) {
         int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
-        Handle<Object> value = JSObject::GetElement(object, i);
+        Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
           __ Addu(a2, result, Operand(*offset));

src/x64/lithium-codegen-x64.cc

@@ -4280,9 +4280,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
         __ movq(FieldOperand(result, total_offset), rcx);
       }
     } else if (elements->IsFixedArray()) {
+      Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
       for (int i = 0; i < elements_length; i++) {
         int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
-        Handle<Object> value = JSObject::GetElement(object, i);
+        Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
           __ lea(rcx, Operand(result, *offset));

test/mjsunit/regress/regress-123512.js

+// Copyright 2012 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+// Test that boilerplate objects for array literals with non-constant
+// elements (which will contain the hole at non-constant positions) will
+// not cause prototype chain lookups when generating optimized code.
+
+function f(x) {
+  return [x][0];
+}
+
+// Test data element on prototype.
+Object.prototype[0] = 23;
+assertSame(1, f(1));
+assertSame(2, f(2));
+%OptimizeFunctionOnNextCall(f);
+assertSame(3, f(3));
+%DeoptimizeFunction(f);
+
+// Test accessor element on prototype.
+Object.prototype.__defineGetter__(0, function() { throw Error(); });
+assertSame(4, f(4));
+assertSame(5, f(5));
+%OptimizeFunctionOnNextCall(f);
+assertSame(6, f(6));
+%DeoptimizeFunction(f);
+
+// Test the same on boilerplate objects for object literals that contain
+// both non-constant properties and non-constant elements.
+
+function g(x, y) {
+  var o = { foo:x, 0:y };
+  return o.foo + o[0];
+}
+
+// Test data property and element on prototype.
+Object.prototype[0] = 23;
+Object.prototype.foo = 42;
+assertSame(3, g(1, 2));
+assertSame(5, g(2, 3));
+%OptimizeFunctionOnNextCall(g);
+assertSame(7, g(3, 4));
+%DeoptimizeFunction(g);
+
+// Test accessor property and element on prototype.
+Object.prototype.__defineGetter__(0, function() { throw Error(); });
+Object.prototype.__defineGetter__('foo', function() { throw Error(); });
+assertSame(3, g(1, 2));
+assertSame(5, g(2, 3));
+%OptimizeFunctionOnNextCall(g);
+assertSame(7, g(3, 4));
+%DeoptimizeFunction(g);