ES6: Array.prototype.slice and friends should use ToLength instead of ToUint32

Defines a new --harmony-tolength flag, and a ToLengthFlagged() runtime function,
that is used where ES6 requires ToLength(), but a pre-ES6 conversion existed
before. When the flag is disabled, the function uses TO_UINT32(), which is
the pre-ES6 behaviour. When the flag enabled, the ES6-compliant ToLength()
conversion is used.

Based on a patch initially from Diego Pino <dpino@igalia.com>

BUG=v8:3087
LOG=Y

Review URL: https://codereview.chromium.org/1309243003

Cr-Commit-Position: refs/heads/master@{#30772}

src/array.js

@@ -395,7 +395,7 @@ function ArrayToString() {
 
 
 function InnerArrayToLocaleString(array, length) {
-  var len = TO_UINT32(length);
+  var len = TO_LENGTH_OR_UINT32(length);
   if (len === 0) return "";
   return Join(array, len, ',', ConvertToLocaleString);
 }
@@ -434,7 +434,7 @@ function ArrayJoin(separator) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.join");
 
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
 
   return InnerArrayJoin(separator, array, length);
 }
@@ -463,7 +463,7 @@ function ArrayPop() {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.pop");
 
   var array = TO_OBJECT(this);
-  var n = TO_UINT32(array.length);
+  var n = TO_LENGTH_OR_UINT32(array.length);
   if (n == 0) {
     array.length = n;
     return;
@@ -481,7 +481,7 @@ function ArrayPop() {
 
 
 function ObservedArrayPush() {
-  var n = TO_UINT32(this.length);
+  var n = TO_LENGTH_OR_UINT32(this.length);
   var m = %_ArgumentsLength();
 
   try {
@@ -509,7 +509,7 @@ function ArrayPush() {
     return ObservedArrayPush.apply(this, arguments);
 
   var array = TO_OBJECT(this);
-  var n = TO_UINT32(array.length);
+  var n = TO_LENGTH_OR_UINT32(array.length);
   var m = %_ArgumentsLength();
 
   for (var i = 0; i < m; i++) {
@@ -606,7 +606,7 @@ function ArrayReverse() {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.reverse");
 
   var array = TO_OBJECT(this);
-  var len = TO_UINT32(array.length);
+  var len = TO_LENGTH_OR_UINT32(array.length);
   var isArray = IS_ARRAY(array);
 
   if (UseSparseVariant(array, len, isArray, len)) {
@@ -641,7 +641,7 @@ function ArrayShift() {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.shift");
 
   var array = TO_OBJECT(this);
-  var len = TO_UINT32(array.length);
+  var len = TO_LENGTH_OR_UINT32(array.length);
 
   if (len === 0) {
     array.length = 0;
@@ -668,7 +668,7 @@ function ArrayShift() {
 
 
 function ObservedArrayUnshift() {
-  var len = TO_UINT32(this.length);
+  var len = TO_LENGTH_OR_UINT32(this.length);
   var num_arguments = %_ArgumentsLength();
 
   try {
@@ -695,7 +695,7 @@ function ArrayUnshift(arg1) {  // length == 1
     return ObservedArrayUnshift.apply(this, arguments);
 
   var array = TO_OBJECT(this);
-  var len = TO_UINT32(array.length);
+  var len = TO_LENGTH_OR_UINT32(array.length);
   var num_arguments = %_ArgumentsLength();
 
   if (len > 0 && UseSparseVariant(array, len, IS_ARRAY(array), len) &&
@@ -719,7 +719,7 @@ function ArraySlice(start, end) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.slice");
 
   var array = TO_OBJECT(this);
-  var len = TO_UINT32(array.length);
+  var len = TO_LENGTH_OR_UINT32(array.length);
   var start_i = TO_INTEGER(start);
   var end_i = len;
 
@@ -790,7 +790,7 @@ function ComputeSpliceDeleteCount(delete_count, num_arguments, len, start_i) {
 
 function ObservedArraySplice(start, delete_count) {
   var num_arguments = %_ArgumentsLength();
-  var len = TO_UINT32(this.length);
+  var len = TO_LENGTH_OR_UINT32(this.length);
   var start_i = ComputeSpliceStartIndex(TO_INTEGER(start), len);
   var del_count = ComputeSpliceDeleteCount(delete_count, num_arguments, len,
                                            start_i);
@@ -837,7 +837,7 @@ function ArraySplice(start, delete_count) {
 
   var num_arguments = %_ArgumentsLength();
   var array = TO_OBJECT(this);
-  var len = TO_UINT32(array.length);
+  var len = TO_LENGTH_OR_UINT32(array.length);
   var start_i = ComputeSpliceStartIndex(TO_INTEGER(start), len);
   var del_count = ComputeSpliceDeleteCount(delete_count, num_arguments, len,
                                            start_i);
@@ -1173,7 +1173,7 @@ function ArraySort(comparefn) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.sort");
 
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   return InnerArraySort(array, length, comparefn);
 }
 
@@ -1207,7 +1207,7 @@ function ArrayFilter(f, receiver) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   var accumulator = InnerArrayFilter(f, receiver, array, length);
   var result = new GlobalArray();
   %MoveArrayContents(accumulator, result);
@@ -1235,7 +1235,7 @@ function ArrayForEach(f, receiver) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   InnerArrayForEach(f, receiver, array, length);
 }
 
@@ -1265,7 +1265,7 @@ function ArraySome(f, receiver) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   return InnerArraySome(f, receiver, array, length);
 }
 
@@ -1292,7 +1292,7 @@ function ArrayEvery(f, receiver) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   return InnerArrayEvery(f, receiver, array, length);
 }
 
@@ -1321,7 +1321,7 @@ function ArrayMap(f, receiver) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   var accumulator = InnerArrayMap(f, receiver, array, length);
   var result = new GlobalArray();
   %MoveArrayContents(accumulator, result);
@@ -1390,7 +1390,7 @@ function InnerArrayIndexOf(array, element, index, length) {
 function ArrayIndexOf(element, index) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.indexOf");
 
-  var length = TO_UINT32(this.length);
+  var length = TO_LENGTH_OR_UINT32(this.length);
   return InnerArrayIndexOf(this, element, index, length);
 }
 
@@ -1448,7 +1448,7 @@ function InnerArrayLastIndexOf(array, element, index, length, argumentsLength) {
 function ArrayLastIndexOf(element, index) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.lastIndexOf");
 
-  var length = TO_UINT32(this.length);
+  var length = TO_LENGTH_OR_UINT32(this.length);
   return InnerArrayLastIndexOf(this, element, index, length,
                         %_ArgumentsLength());
 }
@@ -1490,7 +1490,7 @@ function ArrayReduce(callback, current) {
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping and side effects are visible.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   return InnerArrayReduce(callback, current, array, length,
                           %_ArgumentsLength());
 }
@@ -1533,7 +1533,7 @@ function ArrayReduceRight(callback, current) {
   // Pull out the length so that side effects are visible before the
   // callback function is checked.
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
   return InnerArrayReduceRight(callback, current, array, length,
                                %_ArgumentsLength());
 }

src/bootstrapper.cc

@@ -1860,6 +1860,15 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_unicode_regexps)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tostring)
 
 
+void Genesis::InitializeGlobal_harmony_tolength() {
+  Handle<JSObject> builtins(native_context()->builtins());
+  Handle<Object> flag(factory()->ToBoolean(FLAG_harmony_tolength));
+  Runtime::SetObjectProperty(isolate(), builtins,
+                             factory()->harmony_tolength_string(), flag,
+                             STRICT).Assert();
+}
+
+
 void Genesis::InitializeGlobal_harmony_reflect() {
   if (!FLAG_harmony_reflect) return;
 
@@ -2542,6 +2551,7 @@ bool Genesis::InstallExperimentalNatives() {
       "native harmony-concat-spreadable.js", nullptr};
   static const char* harmony_simd_natives[] = {"native harmony-simd.js",
                                                nullptr};
+  static const char* harmony_tolength_natives[] = {nullptr};
 
   for (int i = ExperimentalNatives::GetDebuggerCount();
        i < ExperimentalNatives::GetBuiltinsCount(); i++) {

src/flag-definitions.h

@@ -194,6 +194,7 @@ DEFINE_BOOL(legacy_const, true, "legacy semantics for const in sloppy mode")
   V(harmony_proxies, "harmony proxies")                               \
   V(harmony_sloppy_function, "harmony sloppy function block scoping") \
   V(harmony_unicode_regexps, "harmony unicode regexps")               \
+  V(harmony_tolength, "harmony ToLength")                             \
   V(harmony_reflect, "harmony Reflect API")                           \
   V(harmony_destructuring, "harmony destructuring")                   \
   V(harmony_default_parameters, "harmony default parameters")         \

src/harmony-array.js

@@ -173,7 +173,7 @@ function ArrayFill(value, start, end) {
   CHECK_OBJECT_COERCIBLE(this, "Array.prototype.fill");
 
   var array = TO_OBJECT(this);
-  var length = TO_UINT32(array.length);
+  var length = TO_LENGTH_OR_UINT32(array.length);
 
   return InnerArrayFill(value, start, end, array, length);
 }

src/heap/heap.h

@@ -258,6 +258,7 @@ namespace internal {
   V(multiline_string, "multiline")                             \
   V(sticky_string, "sticky")                                   \
   V(unicode_string, "unicode")                                 \
+  V(harmony_tolength_string, "harmony_tolength")               \
   V(input_string, "input")                                     \
   V(index_string, "index")                                     \
   V(last_index_string, "lastIndex")                            \

src/macros.py

@@ -147,6 +147,7 @@ macro TO_INTEGER_FOR_SIDE_EFFECT(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : ToNumber(
 macro TO_INTEGER_MAP_MINUS_ZERO(arg) = (%_IsSmi(%IS_VAR(arg)) ? arg : %NumberToIntegerMapMinusZero(ToNumber(arg)));
 macro TO_INT32(arg) = (arg | 0);
 macro TO_UINT32(arg) = (arg >>> 0);
+macro TO_LENGTH_OR_UINT32(arg) = (harmony_tolength ? $toLength(arg) : TO_UINT32(arg));
 macro TO_STRING_INLINE(arg) = (IS_STRING(%IS_VAR(arg)) ? arg : $nonStringToString(arg));
 macro TO_NUMBER_INLINE(arg) = (IS_NUMBER(%IS_VAR(arg)) ? arg : $nonNumberToNumber(arg));
 macro TO_OBJECT(arg) = (%_ToObject(arg));

src/runtime.js

@@ -24,6 +24,8 @@ var $toPositiveInteger;
 var $toPrimitive;
 var $toString;
 
+var harmony_tolength = false;
+
 (function(global, utils) {
 
 %CheckIsBootstrapping();

test/mjsunit/harmony/array-length.js

@@ -0,0 +1,208 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-tolength
+
+// Test array functions do not cause infinite loops when length is negative,
+// max_value, etc.
+
+// ArrayToString
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.toString.call(o);
+assertEquals("[object Object]", result);
+
+// ArrayToLocaleString
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.toLocaleString.call(o);
+assertEquals("", result);
+
+// ArrayJoin
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.join.call(o);
+assertEquals(0, result.length);
+
+// ArrayPush
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.push.call(o, 1);
+assertEquals(1, o.length);
+assertEquals(1, o[0]);
+
+var o = { length: Number.MAX_VALUE };
+Array.prototype.push.call(o, 1);
+assertEquals(o.length, Number.MAX_SAFE_INTEGER + 1);
+assertEquals(1, o[Number.MAX_SAFE_INTEGER]);
+
+Array.prototype.push.call(o, 2);
+assertEquals(o.length, Number.MAX_SAFE_INTEGER + 1);
+assertEquals(2, o[Number.MAX_SAFE_INTEGER]);
+
+// ArrayPop
+
+var o = { length: 0 };
+Array.prototype.pop.call(o);
+assertEquals(0, o.length);
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.pop.call(o);
+assertEquals(0, o.length);
+
+var o = { length: Number.MAX_VALUE };
+Array.prototype.pop.call(o);
+assertEquals(o.length, Number.MAX_SAFE_INTEGER - 1);
+
+// ArrayReverse
+
+var o = { 0: 'foo', length: Number.MIN_VALUE }
+var result = Array.prototype.reverse.call(o);
+assertEquals('object', typeof(result));
+assertEquals(Number.MIN_VALUE, result.length);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayShift
+
+var o = { 0: "foo", length: Number.MIN_VALUE }
+var result = Array.prototype.shift.call(o);
+assertEquals(undefined, result);
+assertEquals(0, o.length);
+
+// ArrayUnshift
+
+var o = { length: 0 };
+Array.prototype.unshift.call(o);
+assertEquals(0, o.length);
+
+var o = { length: 0 };
+Array.prototype.unshift.call(o, 'foo');
+assertEquals('foo', o[0]);
+assertEquals(1, o.length);
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.unshift.call(o);
+assertEquals(0, o.length);
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.unshift.call(o, 'foo');
+assertEquals('foo', o[0]);
+assertEquals(1, o.length);
+
+// ArraySplice
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.splice.call(o);
+assertEquals(0, o.length);
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.splice.call(o, 0, 10, ['foo']);
+assertEquals(['foo'], o[0]);
+assertEquals(1, o.length);
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.splice.call(o, -1);
+assertEquals(0, o.length);
+
+var o = { length: Number.MAX_SAFE_INTEGER };
+Array.prototype.splice.call(o, -1);
+assertEquals(Number.MAX_SAFE_INTEGER - 1, o.length);
+
+// ArraySlice
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.slice.call(o);
+assertEquals(0, result.length);
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.slice.call(o, Number.MAX_VALUE);
+assertEquals(0, result.length);
+
+var o = { length: Number.MAX_VALUE };
+var result = Array.prototype.slice.call(o, Number.MAX_VALUE - 1);
+assertEquals(0, result.length);
+
+// ArrayIndexOf
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.indexOf.call(o);
+assertEquals(-1, result);
+
+var o = { length: Number.MAX_SAFE_INTEGER }
+o[Number.MAX_SAFE_INTEGER - 1] = "foo"
+var result = Array.prototype.indexOf.call(o,
+    "foo", Number.MAX_SAFE_INTEGER - 2);
+assertEquals(Number.MAX_SAFE_INTEGER - 1, result);
+
+var o = { length: Number.MAX_SAFE_INTEGER };
+o[Number.MAX_SAFE_INTEGER - 1] = "foo";
+var result = Array.prototype.indexOf.call(o, "foo", -1);
+assertEquals(Number.MAX_SAFE_INTEGER - 1, result);
+
+// ArrayLastIndexOf
+
+var o = { length: Number.MIN_VALUE };
+var result = Array.prototype.lastIndexOf.call(o);
+assertEquals(-1, result);
+
+var o = { length: Number.MAX_SAFE_INTEGER }
+o[Number.MAX_SAFE_INTEGER - 1] = "foo"
+var result = Array.prototype.lastIndexOf.call(o,
+    "foo", Number.MAX_SAFE_INTEGER);
+assertEquals(Number.MAX_SAFE_INTEGER - 1, result);
+
+var o = { length: Number.MAX_SAFE_INTEGER };
+o[Number.MAX_SAFE_INTEGER - 1] = "foo";
+var result = Array.prototype.lastIndexOf.call(o, "foo", -1);
+assertEquals(Number.MAX_SAFE_INTEGER - 1, result);
+
+// ArrayFilter
+
+var func = function(v) { return v; }
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.filter.call(o, func);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayForEach
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.forEach.call(o, func);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArraySome
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.some.call(o, func);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayEvery
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.every.call(o, func);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayMap
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.map.call(o, func);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayReduce
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.reduce.call(o, func, 0);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayReduceRight
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.reduceRight.call(o, func, 0);
+assertEquals(Number.MIN_VALUE, o.length);
+
+// ArrayFill
+
+var o = { length: Number.MIN_VALUE };
+Array.prototype.fill(o, 0);
+assertEquals(Number.MIN_VALUE, o.length);