fix for js optimizer not noticing globals are modified
This commit is contained in:
Alon Zakai
Родитель
9a004a8fa1
Коммит
580d7f6408
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@ -35,7 +35,7 @@ var FUNCTION = set('defun', 'function');
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// it replaces the passed node in the tree.
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// @arg post: A callback to call after traversing all children.
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// @arg stack: If true, a stack will be implemented: If pre does not push on
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// the stack, we push a null. We pop when we leave the node. The
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// the stack, we push a 0. We pop when we leave the node. The
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// stack is passed as a third parameter to the callbacks.
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// @returns: If the root node was replaced, the new root node. If the traversal
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// was stopped, true. Otherwise undefined.
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@ -46,7 +46,7 @@ function traverse(node, pre, post, stack) {
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if (stack) len = stack.length;
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var result = pre(node, type, stack);
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if (result == true) return true;
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if (stack && len == stack.length) stack.push(null);
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if (stack && len == stack.length) stack.push(0);
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}
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for (var i = 0; i < node.length; i++) {
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var subnode = node[i];
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@ -66,45 +66,8 @@ function traverse(node, pre, post, stack) {
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return result;
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}
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function makeEmptyNode() {
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return ['toplevel', []]
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}
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// Passes
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// Undos closure's creation of global variables with values true, false,
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// undefined, null. These cut down on size, but do not affect gzip size
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// and make JS engine's lives slightly harder (?)
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function unGlobalize(ast) {
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assert(ast[0] == 'toplevel');
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var values = {};
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// Find global renamings of the relevant values
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ast[1].forEach(function(node, i) {
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if (node[0] != 'var') return;
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node[1] = node[1].filter(function(varItem) {
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var key = varItem[0];
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var value = varItem[1];
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if (!value) return true;
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if (value[0] == 'name' && value[1] == 'null') {
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values[key] = ['name','null'];
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return false;
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} else if (value[0] == 'unary-prefix' && value[1] == 'void' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 0){
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values[key] = ['unary-prefix','void',['num',0]];
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return false;
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} else if (value[0] == 'unary-prefix' && value[1] == '!' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 0){
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values[key] = ['unary-prefix','!',['num',0]];
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return false;
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} else if (value[0] == 'unary-prefix' && value[1] == '!' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 1){
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values[key] = ['unary-prefix','!',['num',1]];
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return false;
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}
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return true;
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});
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if (node[1].length == 0) {
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ast[1][i] = makeEmptyNode();
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}
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});
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// Walk the ast, with an understanding of JS variable scope (i.e., function-level scoping)
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// Walk the ast in a simple way, with an understanding of which JS variables are defined)
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function traverseWithVariables(ast, callback) {
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traverse(ast, function(node, type, stack) {
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if (type in FUNCTION) {
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stack.push({ type: 'function', vars: node[2] });
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@ -121,21 +84,72 @@ function unGlobalize(ast) {
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var allVars = stack.map(function(item) { return item ? item.vars : [] }).reduce(concatenator, []); // FIXME dictionary for speed?
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traverse(node, function(node, type, stack) {
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// Be careful not to look into our inner functions. They have already been processed.
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if (type == 'name' && sum(stack) == 1) {
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var ident = node[1];
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if (ident in values && allVars.indexOf(ident) < 0) {
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return copy(values[ident]);
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}
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} else if (type in FUNCTION) {
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stack.push(1);
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} else {
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stack.push(0);
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}
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if (sum(stack) > 1) return;
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if (type in FUNCTION) stack.push(1);
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return callback(node, type, allVars);
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}, null, []);
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}
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}, []);
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}
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function makeEmptyNode() {
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return ['toplevel', []]
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}
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// Passes
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// Undos closure's creation of global variables with values true, false,
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// undefined, null. These cut down on size, but do not affect gzip size
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// and make JS engine's lives slightly harder (?)
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function unGlobalize(ast) {
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assert(ast[0] == 'toplevel');
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var values = {};
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// Find global renamings of the relevant values
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ast[1].forEach(function(node, i) {
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if (node[0] != 'var') return;
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node[1] = node[1].filter(function(varItem, j) {
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var ident = varItem[0];
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var value = varItem[1];
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if (!value) return true;
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var possible = false;
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if (value[0] == 'name' && value[1] == 'null') {
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possible = true;
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} else if (value[0] == 'unary-prefix' && value[1] == 'void' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 0) {
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possible = true;
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} else if (value[0] == 'unary-prefix' && value[1] == '!' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 0) {
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possible = true;
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} else if (value[0] == 'unary-prefix' && value[1] == '!' && value[2] && value[2].length == 2 && value[2][0] == 'num' && value[2][1] == 1) {
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possible = true;
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}
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if (!possible) return true;
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// Make sure there are no assignments to this variable. (This isn't fast, we traverse many times..)
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ast[1][i][1][j] = makeEmptyNode();
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var assigned = false;
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traverseWithVariables(ast, function(node, type, allVars) {
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if (type == 'assign' && node[2][0] == 'name' && node[2][1] == ident) assigned = true;
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});
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ast[1][i][1][j] = [ident, value];
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if (!assigned) {
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values[ident] = value;
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return false;
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}
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return true;
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});
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if (node[1].length == 0) {
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ast[1][i] = makeEmptyNode();
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}
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});
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traverseWithVariables(ast, function(node, type, allVars) {
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if (type == 'name') {
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var ident = node[1];
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if (ident in values && allVars.indexOf(ident) < 0) {
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return copy(values[ident]);
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}
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}
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});
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}
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// Main
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var src = fs.readFileSync('/dev/stdin').toString();
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@ -1,6 +1,6 @@
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var c;
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var b = 5;
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var s3 = !0;
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function abc() {
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var cheez = void 0;
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var fleefl;
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@ -11,6 +11,7 @@ function abc() {
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var waka3 = void 0, flake3 = 5, marfoosh3 = void 0;
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var waka4 = void 0, flake4 = void 0, marfoosh4 = 5;
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var test1 = !0, test2 = !1, test3 = null, test4 = z, test5 = b, test6 = void 0;
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s3 = 9;
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}
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function xyz() {
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var x = 52;
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@ -24,6 +25,7 @@ function xyz() {
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var i = x, j = null, k = 5, l = t, m = s2;
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var s2 = 8;
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});
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var patama = s3;
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}
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function xyz2(x) {
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var cheez = x;
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@ -1,6 +1,6 @@
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var c;
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var b = 5, x = void 0, y = null, t = !0;
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var s = !1, s2 = !1;
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var s = !1, s2 = !1, s3 = !0;
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function abc() {
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var cheez = x;
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var fleefl;
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@ -11,6 +11,7 @@ function abc() {
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var waka3 = x, flake3 = 5, marfoosh3 = x;
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var waka4 = x, flake4 = x, marfoosh4 = 5;
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var test1 = t, test2 = s, test3 = y, test4 = z, test5 = b, test6 = x;
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s3 = 9;
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}
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function xyz() {
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var x = 52;
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@ -24,6 +25,7 @@ function xyz() {
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var i = x, j = y, k = 5, l = t, m = s2;
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var s2 = 8;
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};
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var patama = s3;
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}
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function xyz2(x) {
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var cheez = x;
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