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[math] Fix Math.hypot to properly call ToNumber on all arguments.

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The spec requires all Math functions to first call ToNumber on all
arguments before doing any other observable operation.  So early
return in case of Infinity is not valid.

Drive-by-fix: Remove the use of %_Arguments / %_ArgumentsLength and
use (strict) arguments instead of allocating a temporary InternalArray
explicitly.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1669773002

Cr-Commit-Position: refs/heads/master@{#33717}
This commit is contained in:
bmeurer 2016-02-03 23:22:39 -08:00 committed by Commit bot
parent db74cccf8a
commit 264fa75e52
2 changed files with 12 additions and 8 deletions
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13
src/js/math.js
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@ -164,17 +164,14 @@ function MathHypot(x, y) { // Function length is 2.
// We may want to introduce fast paths for two arguments and when
// normalization to avoid overflow is not necessary. For now, we
// simply assume the general case.
var length = %_ArgumentsLength();
var args = new InternalArray(length);
var length = arguments.length;
var max = 0;
for (var i = 0; i < length; i++) {
var n = %_Arguments(i);
n = TO_NUMBER(n);
if (n === INFINITY || n === -INFINITY) return INFINITY;
n = MathAbs(n);
var n = MathAbs(arguments[i]);
if (n > max) max = n;
args[i] = n;
arguments[i] = n;
}
if (max === INFINITY) return INFINITY;
// Kahan summation to avoid rounding errors.
// Normalize the numbers to the largest one to avoid overflow.
@ -182,7 +179,7 @@ function MathHypot(x, y) { // Function length is 2.
var sum = 0;
var compensation = 0;
for (var i = 0; i < length; i++) {
var n = args[i] / max;
var n = arguments[i] / max;
var summand = n * n - compensation;
var preliminary = sum + summand;
compensation = (preliminary - sum) - summand;

7
test/mjsunit/to_number_order.js
View File

@ -56,6 +56,13 @@ x = "";
assertEquals(1, Math.pow(v, w));
assertEquals("hestfisk", x, "pow");
x = "";
var a = {valueOf: function() { x += "hest"; return 1/0; }};
var b = {valueOf: function() { x += "fisk"; return 1}};
assertEquals(1/0, Math.hypot(a, b));
assertEquals("hestfisk", x, "hypot");
var year = { valueOf: function() { x += 1; return 2007; } };
var month = { valueOf: function() { x += 2; return 2; } };
var date = { valueOf: function() { x += 3; return 4; } };