src: Use simple/fast macro version of MinMax in JS

src/arraybuffer.js

 // Copyright 2013 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.
 
 (function(global, utils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
 
 var GlobalArrayBuffer = global.ArrayBuffer;
 var GlobalObject = global.Object;
-var MathMax;
-var MathMin;
 var ToNumber;
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 
 utils.Import(function(from) {
-  MathMax = from.MathMax;
-  MathMin = from.MathMin;
   ToNumber = from.ToNumber;
 });
 
 // -------------------------------------------------------------------
 
 function ArrayBufferConstructor(length) { // length = 1
   if (%_IsConstructCall()) {
     var byteLength = $toPositiveInteger(length, kInvalidArrayBufferLength);
     %ArrayBufferInitialize(this, byteLength, kNotShared);
   } else {
     throw MakeTypeError(kConstructorNotFunction, "ArrayBuffer");
   }
 }
 
 function ArrayBufferGetByteLen() {
   if (!IS_ARRAYBUFFER(this)) {
     throw MakeTypeError(kIncompatibleMethodReceiver,
                         'ArrayBuffer.prototype.byteLength', this);
   }
   return %_ArrayBufferGetByteLength(this);
 }
 
 // ES6 Draft 15.13.5.5.3
 function ArrayBufferSlice(start, end) {
   if (!IS_ARRAYBUFFER(this)) {
     throw MakeTypeError(kIncompatibleMethodReceiver,
                         'ArrayBuffer.prototype.slice', this);
   }
 
-  var relativeStart = TO_INTEGER(start);
+  var startInt = TO_INTEGER(start);
   if (!IS_UNDEFINED(end)) {
-    end = TO_INTEGER(end);
-  }
-  var first;
-  var byte_length = %_ArrayBufferGetByteLength(this);
-  if (relativeStart < 0) {
-    first = MathMax(byte_length + relativeStart, 0);
+    var endInt = TO_INTEGER(end);
+    var byteLength = %_ArrayBufferGetByteLength(this);
   } else {
-    first = MathMin(relativeStart, byte_length);
-  }
-  var relativeEnd = IS_UNDEFINED(end) ? byte_length : end;
-  var fin;
-  if (relativeEnd < 0) {
-    fin = MathMax(byte_length + relativeEnd, 0);
-  } else {
-    fin = MathMin(relativeEnd, byte_length);
+    var byteLength = %_ArrayBufferGetByteLength(this);

[Dan Ehrenberg, 2015/09/16 21:34:21]

Why did you move this inside of the conditional rather than before it?

[skomski, 2015/09/16 21:57:39]

Same code as in SubArray; related to https://codereview.chromium.org/201873005.

[Jakob Kummerow, 2015/09/17 07:36:34]

That's not a good reason. It didn't make sense there, it doesn't make sense here
either.

[skomski, 2015/09/17 08:07:03]

First one was not a reason rather I thought he missed that it's the same
construct but the main reason was the related bit.

1) TO_INTEGER needs to be called always before GetByteLength
(https://codereview.chromium.org/201873005)
2) IS_UNDEFINED does not need to be called twice

results into this construct.

+    var endInt = byteLength;
   }
 
-  if (fin < first) {
-    fin = first;
+  if (startInt < 0) {
+    startInt = MAX_SIMPLE(byteLength + startInt, 0);
+  } else {
+    startInt = MIN_SIMPLE(startInt, byteLength);
   }
-  var newLen = fin - first;
+
+  if (endInt < 0) {
+    endInt = MAX_SIMPLE(byteLength + endInt, 0);
+  } else {
+    endInt = MIN_SIMPLE(endInt, byteLength);
+  }
+
+  if (endInt < startInt) {
+    endInt = startInt;
+  }
+
+  var newLength = endInt - startInt;
   // TODO(dslomov): implement inheritance
-  var result = new GlobalArrayBuffer(newLen);
+  var result = new GlobalArrayBuffer(newLength);
 
-  %ArrayBufferSliceImpl(this, result, first);
+  %ArrayBufferSliceImpl(this, result, startInt);
   return result;
 }
 
 function ArrayBufferIsViewJS(obj) {
   return %ArrayBufferIsView(obj);
 }
 
 
 // Set up the ArrayBuffer constructor function.
 %SetCode(GlobalArrayBuffer, ArrayBufferConstructor);
@@ skipping 11 matching lines @@
 
 utils.InstallFunctions(GlobalArrayBuffer, DONT_ENUM, [
   "isView", ArrayBufferIsViewJS
 ]);
 
 utils.InstallFunctions(GlobalArrayBuffer.prototype, DONT_ENUM, [
   "slice", ArrayBufferSlice
 ]);
 
 })