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fix corner case in ie8 (#3216)
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fixes #3215
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@alexlamsl
alexlamsl committed Jul 19, 2018
1 parent 8d4b534 commit cea685f
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Showing 7 changed files with 350 additions and 100 deletions.
84 changes: 40 additions & 44 deletions lib/compress.js
View file
Expand Up @@ -1264,6 +1264,9 @@ merge(Compressor.prototype, {
if (node instanceof AST_Exit) {
return side_effects || lhs instanceof AST_PropAccess || may_modify(lhs);
}
if (node instanceof AST_Function) {
return compressor.option("ie8") && node.name && node.name.name in lvalues;
}
if (node instanceof AST_PropAccess) {
return side_effects || node.expression.may_throw_on_access(compressor);
}
Expand Down Expand Up @@ -1610,10 +1613,7 @@ merge(Compressor.prototype, {
if (def.orig.length == 1 && def.orig[0] instanceof AST_SymbolDefun) return false;
if (def.scope !== scope) return true;
return !all(def.references, function(ref) {
var s = ref.scope;
// "block" scope within AST_Catch
if (s.TYPE == "Scope") s = s.parent_scope;
return s === scope;
return ref.scope.resolve() === scope;
});
}

Expand Down Expand Up @@ -2704,35 +2704,30 @@ merge(Compressor.prototype, {
if (right === this.right) return this;
var result;
switch (this.operator) {
case "&&" : result = left && right; break;
case "||" : result = left || right; break;
case "|" : result = left | right; break;
case "&" : result = left & right; break;
case "^" : result = left ^ right; break;
case "+" : result = left + right; break;
case "*" : result = left * right; break;
case "/" : result = left / right; break;
case "%" : result = left % right; break;
case "-" : result = left - right; break;
case "<<" : result = left << right; break;
case ">>" : result = left >> right; break;
case ">>>" : result = left >>> right; break;
case "==" : result = left == right; break;
case "===" : result = left === right; break;
case "!=" : result = left != right; break;
case "!==" : result = left !== right; break;
case "<" : result = left < right; break;
case "<=" : result = left <= right; break;
case ">" : result = left > right; break;
case ">=" : result = left >= right; break;
default:
return this;
}
if (isNaN(result) && compressor.find_parent(AST_With)) {
// leave original expression as is
return this;
}
return result;
case "&&" : result = left && right; break;
case "||" : result = left || right; break;
case "|" : result = left | right; break;
case "&" : result = left & right; break;
case "^" : result = left ^ right; break;
case "+" : result = left + right; break;
case "*" : result = left * right; break;
case "/" : result = left / right; break;
case "%" : result = left % right; break;
case "-" : result = left - right; break;
case "<<" : result = left << right; break;
case ">>" : result = left >> right; break;
case ">>>": result = left >>> right; break;
case "==" : result = left == right; break;
case "===": result = left === right; break;
case "!=" : result = left != right; break;
case "!==": result = left !== right; break;
case "<" : result = left < right; break;
case "<=" : result = left <= right; break;
case ">" : result = left > right; break;
case ">=" : result = left >= right; break;
default : return this;
}
return isNaN(result) && compressor.find_parent(AST_With) ? this : result;
});
def(AST_Conditional, function(compressor, cached, depth) {
var condition = this.condition._eval(compressor, cached, depth);
Expand Down Expand Up @@ -3412,6 +3407,14 @@ merge(Compressor.prototype, {
init.walk(tw);
});
}
var drop_fn_name = compressor.option("keep_fnames") ? return_false : compressor.option("ie8") ? function(def) {
return !compressor.exposed(def) && !def.references.length;
} : function(def) {
// any declarations with same name will overshadow
// name of this anonymous function and can therefore
// never be used anywhere
return !(def.id in in_use_ids) || def.orig.length > 1;
};
// pass 3: we should drop declarations not in_use
var tt = new TreeTransformer(function(node, descend, in_list) {
var parent = tt.parent();
Expand Down Expand Up @@ -3439,15 +3442,8 @@ merge(Compressor.prototype, {
}
}
if (scope !== self) return;
if (node instanceof AST_Function
&& node.name
&& !compressor.option("ie8")
&& !compressor.option("keep_fnames")) {
var def = node.name.definition();
// any declarations with same name will overshadow
// name of this anonymous function and can therefore
// never be used anywhere
if (!(def.id in in_use_ids) || def.orig.length > 1) node.name = null;
if (node instanceof AST_Function && node.name && drop_fn_name(node.name.definition())) {
node.name = null;
}
if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) {
var trim = !compressor.option("keep_fargs");
Expand Down Expand Up @@ -5726,10 +5722,10 @@ merge(Compressor.prototype, {
if (def) {
return def.optimize(compressor);
}
// testing against !self.scope.uses_with first is an optimization
if (!compressor.option("ie8")
&& is_undeclared_ref(self)
&& (!self.scope.uses_with || !compressor.find_parent(AST_With))) {
// testing against `self.scope.uses_with` is an optimization
&& !(self.scope.uses_with && compressor.find_parent(AST_With))) {
switch (self.name) {
case "undefined":
return make_node(AST_Undefined, self).optimize(compressor);
Expand Down
95 changes: 51 additions & 44 deletions lib/scope.js
View file
Expand Up @@ -118,11 +118,10 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
descend();
scope = save_scope;
defun = save_defun;
return true; // don't descend again in TreeWalker
return true;
}
if (node instanceof AST_With) {
for (var s = scope; s; s = s.parent_scope)
s.uses_with = true;
for (var s = scope; s; s = s.parent_scope) s.uses_with = true;
return;
}
if (node instanceof AST_Symbol) {
Expand All @@ -132,18 +131,13 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
node.thedef = node;
node.references = [];
}
if (node instanceof AST_SymbolDefun || options.ie8 && node instanceof AST_SymbolLambda) {
// Careful here, the scope where this should be defined is
// the parent scope. The reason is that we enter a new
// scope when we encounter the AST_Defun node (which is
// instanceof AST_Scope) but we get to the symbol a bit
// later.
(node.scope = defun.parent_scope).def_function(node, defun);
}
else if (node instanceof AST_SymbolLambda) {
if (node instanceof AST_SymbolDefun) {
// This should be defined in the parent scope, as we encounter the
// AST_Defun node before getting to its AST_Symbol.
(node.scope = defun.parent_scope.resolve()).def_function(node, defun);
} else if (node instanceof AST_SymbolLambda) {
defun.def_function(node, node.name == "arguments" ? undefined : defun);
}
else if (node instanceof AST_SymbolVar) {
} else if (node instanceof AST_SymbolVar) {
defun.def_variable(node, node.TYPE == "SymbolVar" ? null : undefined);
if (defun !== scope) {
node.mark_enclosed(options);
Expand All @@ -153,18 +147,17 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
}
node.reference(options);
}
}
else if (node instanceof AST_SymbolCatch) {
} else if (node instanceof AST_SymbolCatch) {
scope.def_variable(node).defun = defun;
}
});
self.walk(tw);

// pass 2: find back references and eval
self.globals = new Dictionary();
var tw = new TreeWalker(function(node, descend) {
if (node instanceof AST_LoopControl && node.label) {
node.label.thedef.references.push(node);
var tw = new TreeWalker(function(node) {
if (node instanceof AST_LoopControl) {
if (node.label) node.label.thedef.references.push(node);
return true;
}
if (node instanceof AST_SymbolRef) {
Expand All @@ -185,35 +178,43 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
return true;
}
// ensure mangling works if catch reuses a scope variable
var def;
if (node instanceof AST_SymbolCatch && (def = node.definition().redefined())) {
var s = node.scope;
while (s) {
if (node instanceof AST_SymbolCatch) {
var def = node.definition().redefined();
if (def) for (var s = node.scope; s; s = s.parent_scope) {
push_uniq(s.enclosed, def);
if (s === def.scope) break;
s = s.parent_scope;
}
return true;
}
});
self.walk(tw);

// pass 3: fix up any scoping issue with IE8
if (options.ie8) {
self.walk(new TreeWalker(function(node, descend) {
if (node instanceof AST_SymbolCatch) {
var name = node.name;
var refs = node.thedef.references;
var scope = node.thedef.defun;
var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node);
refs.forEach(function(ref) {
ref.thedef = def;
ref.reference(options);
});
node.thedef = def;
node.reference(options);
return true;
if (options.ie8) self.walk(new TreeWalker(function(node) {
if (node instanceof AST_SymbolCatch) {
redefine(node, node.thedef.defun);
return true;
}
if (node instanceof AST_SymbolLambda) {
var def = node.thedef;
if (def.orig.length == 1) {
redefine(node, node.scope.parent_scope);
node.thedef.init = def.init;
}
}));
return true;
}
}));

function redefine(node, scope) {
var name = node.name;
var refs = node.thedef.references;
var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node);
refs.forEach(function(ref) {
ref.thedef = def;
ref.reference(options);
});
node.thedef = def;
node.reference(options);
}
});

Expand Down Expand Up @@ -252,16 +253,14 @@ AST_Lambda.DEFMETHOD("init_scope_vars", function() {

AST_Symbol.DEFMETHOD("mark_enclosed", function(options) {
var def = this.definition();
var s = this.scope;
while (s) {
for (var s = this.scope; s; s = s.parent_scope) {
push_uniq(s.enclosed, def);
if (options.keep_fnames) {
s.functions.each(function(d) {
push_uniq(def.scope.enclosed, d);
});
}
if (s === def.scope) break;
s = s.parent_scope;
}
});

Expand Down Expand Up @@ -298,6 +297,12 @@ AST_Scope.DEFMETHOD("def_variable", function(symbol, init) {
return symbol.thedef = def;
});

AST_Lambda.DEFMETHOD("resolve", return_this);
AST_Scope.DEFMETHOD("resolve", function() {
return this.parent_scope;
});
AST_Toplevel.DEFMETHOD("resolve", return_this);

function names_in_use(scope, options) {
var names = scope.names_in_use;
if (!names) {
Expand Down Expand Up @@ -410,7 +415,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
var save_nesting = lname;
descend();
lname = save_nesting;
return true; // don't descend again in TreeWalker
return true;
}
if (node instanceof AST_Scope) {
descend();
Expand All @@ -422,7 +427,9 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
}
if (node instanceof AST_Label) {
var name;
do name = base54(++lname); while (!is_identifier(name));
do {
name = base54(++lname);
} while (!is_identifier(name));
node.mangled_name = name;
return true;
}
Expand Down
5 changes: 2 additions & 3 deletions lib/utils.js
View file
Expand Up @@ -172,9 +172,8 @@ function string_template(text, props) {
}

function remove(array, el) {
for (var i = array.length; --i >= 0;) {
if (array[i] === el) array.splice(i, 1);
}
var index = array.indexOf(el);
if (index >= 0) array.splice(index, 1);
}

function makePredicate(words) {
Expand Down

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