300 lines
10 KiB
JavaScript
300 lines
10 KiB
JavaScript
AST_Toplevel.DEFMETHOD("figure_out_scope", function(){
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// This does what ast_add_scope did in UglifyJS v1.
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//
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// Part of it could be done at parse time, but it would complicate
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// the parser (and it's already kinda complex). It's also worth
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// having it separated because we might need to call it multiple
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// times on the same tree.
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// pass 1: setup scope chaining and handle definitions
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var scope = this.parent_scope;
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var labels = {};
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_Scope) {
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node.init_scope_vars();
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var save_scope = node.parent_scope = scope;
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scope = node;
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descend();
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scope = save_scope;
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return true; // don't descend again in TreeWalker
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}
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if (node instanceof AST_With) {
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for (var s = scope; s; s = s.parent_scope)
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s.uses_with = true;
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return;
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}
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if (node instanceof AST_LabeledStatement) {
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var l = node.label;
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if (labels[l.name])
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throw new Error(string_template("Label {name} defined twice", l));
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labels[l.name] = l;
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descend();
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delete labels[l.name];
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return true; // no descend again
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}
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if (node instanceof AST_SymbolDeclaration) {
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node.init_scope_vars();
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}
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if (node instanceof AST_SymbolLambda) {
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scope.def_function(node);
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}
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else if (node instanceof AST_SymbolDefun) {
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// Careful here, the scope where this should be defined is
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// the parent scope. The reason is that we enter a new
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// scope when we encounter the AST_Defun node (which is
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// instanceof AST_Scope) but we get to the symbol a bit
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// later.
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scope.parent_scope.def_function(node);
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}
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else if (node instanceof AST_SymbolVar) {
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scope.def_variable(node);
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}
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else if (node instanceof AST_SymbolCatch) {
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// XXX: this is wrong according to ECMA-262 (12.4). the
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// `catch` argument name should be visible only inside the
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// catch block. For a quick fix AST_Catch should inherit
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// from AST_Scope. Keeping it this way because of IE,
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// which doesn't obey the standard. (it introduces the
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// identifier in the enclosing scope)
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scope.def_variable(node);
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}
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else if (node instanceof AST_SymbolRef) {
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node.scope = scope;
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}
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if (node instanceof AST_LabelRef) {
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var sym = labels[node.name];
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if (!sym) throw new Error("Undefined label " + node.name);
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node.reference(sym);
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}
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});
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this.walk(tw);
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// pass 2: find back references and eval
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var func = null;
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_Lambda) {
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var prev_func = func;
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func = node;
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descend();
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func = prev_func;
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return true;
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}
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if (node instanceof AST_SymbolRef) {
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var sym = node.scope.find_variable(node);
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node.reference(sym);
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if (!sym) {
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if (node.name == "eval") {
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for (var s = node.scope;
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s && !s.uses_eval;
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s = s.parent_scope) s.uses_eval = true;
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}
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if (node.name == "arguments") {
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func.uses_arguments = true;
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}
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}
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}
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});
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this.walk(tw);
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});
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AST_Scope.DEFMETHOD("init_scope_vars", function(){
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this.variables = {}; // map name to AST_SymbolVar (variables defined in this scope; includes functions)
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this.functions = {}; // map name to AST_SymbolDefun (functions defined in this scope)
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this.uses_with = false; // will be set to true if this or some nested scope uses the `with` statement
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this.uses_eval = false; // will be set to true if this or nested scope uses the global `eval`
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this.parent_scope = null; // the parent scope
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this.enclosed = []; // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
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this.cname = -1; // the current index for mangling functions/variables
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});
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AST_Lambda.DEFMETHOD("init_scope_vars", function(){
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AST_Scope.prototype.init_scope_vars.call(this);
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this.uses_arguments = false;
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});
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AST_SymbolDeclaration.DEFMETHOD("init_scope_vars", function(){
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this.references = [];
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});
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AST_Toplevel.DEFMETHOD("scope_warnings", function(options){
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options = defaults(options, {
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undeclared : false, // this makes a lot of noise
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unreferenced : true,
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assign_to_global : true,
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func_arguments : true,
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eval : true
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});
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var tw = new TreeWalker(function(node){
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if (options.undeclared
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&& node instanceof AST_SymbolRef
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&& node.undeclared)
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{
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// XXX: this also warns about JS standard names,
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// i.e. Object, Array, parseInt etc. Should add a list of
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// exceptions.
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AST_Node.warn("Undeclared symbol: {name} [{line},{col}]", {
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name: node.name,
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line: node.start.line,
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col: node.start.col
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});
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}
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if (options.assign_to_global)
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{
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var sym = null;
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if (node instanceof AST_Assign && node.left instanceof AST_SymbolRef)
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sym = node.left;
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else if (node instanceof AST_ForIn && node.init instanceof AST_SymbolRef)
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sym = node.init;
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if (sym
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&& (sym.undeclared
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|| (sym.symbol.global
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&& sym.scope !== sym.symbol.scope))) {
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AST_Node.warn("{msg}: {name} [{line},{col}]", {
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msg: sym.undeclared ? "Accidental global?" : "Assignment to global",
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name: sym.name,
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line: sym.start.line,
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col: sym.start.col
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});
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}
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}
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if (options.eval
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&& node instanceof AST_SymbolRef
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&& node.undeclared
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&& node.name == "eval") {
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AST_Node.warn("Eval is used [{line},{col}]", node.start);
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}
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if (options.unreferenced
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&& node instanceof AST_SymbolDeclaration
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&& node.unreferenced()) {
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AST_Node.warn("{type} {name} is declared but not referenced [{line},{col}]", {
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type: node instanceof AST_Label ? "Label" : "Symbol",
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name: node.name,
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line: node.start.line,
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col: node.start.col
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});
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}
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if (options.func_arguments
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&& node instanceof AST_Lambda
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&& node.uses_arguments) {
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AST_Node.warn("arguments used in function {name} [{line},{col}]", {
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name: node.name ? node.name.name : "anonymous",
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line: node.start.line,
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col: node.start.col
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});
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}
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});
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this.walk(tw);
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});
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AST_SymbolRef.DEFMETHOD("reference", function(symbol) {
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if (symbol) {
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this.symbol = symbol;
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var origin = symbol.scope;
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symbol.references.push(this);
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for (var s = this.scope; s; s = s.parent_scope) {
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push_uniq(s.enclosed, symbol);
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if (s === origin) break;
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}
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} else {
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this.undeclared = true;
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for (var s = this.scope; s; s = s.parent_scope) {
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push_uniq(s.enclosed, this);
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}
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}
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});
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AST_Scope.DEFMETHOD("find_variable", function(name){
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if (name instanceof AST_Symbol) name = name.name;
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return this.variables[name] ||
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(this.name && this.name.name == name && this.name) ||
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(this.parent_scope && this.parent_scope.find_variable(name));
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});
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AST_Scope.DEFMETHOD("def_function", function(symbol){
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this.functions[symbol.name] = symbol;
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this.def_variable(symbol);
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});
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AST_Scope.DEFMETHOD("def_variable", function(symbol){
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symbol.global = !this.parent_scope;
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var existing = this.variables[symbol.name];
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if (!existing) {
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this.variables[symbol.name] = symbol;
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} else {
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symbol.uniq = existing;
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}
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symbol.scope = this;
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});
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AST_Scope.DEFMETHOD("next_mangled", function(){
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var ext = this.enclosed, n = ext.length;
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out: while (true) {
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var m = base54(++this.cname);
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if (!is_identifier(m)) continue; // skip over "do"
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// we must ensure that the mangled name does not shadow a name
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// from some parent scope that is referenced in this or in
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// inner scopes.
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for (var i = n; --i >= 0;) {
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var sym = ext[i];
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var name = sym.mangled_name || sym.name;
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if (m == name) continue out;
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}
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return m;
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}
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});
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AST_SymbolDeclaration.DEFMETHOD("mangle", function(){
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if (this.uniq) {
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this.uniq.mangle();
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}
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else if (!(this.global
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|| this.scope.uses_eval
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|| this.scope.uses_with
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|| this.mangled_name)) {
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this.mangled_name = this.scope.next_mangled();
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}
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});
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AST_Label.DEFMETHOD("mangle", function(){
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throw new Error("Don't call this");
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});
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AST_SymbolDeclaration.DEFMETHOD("unreferenced", function(){
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return this.definition().references.length == 0;
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});
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AST_SymbolDeclaration.DEFMETHOD("definition", function(){
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return this.uniq || this;
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});
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AST_Toplevel.DEFMETHOD("mangle_names", function(){
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// We only need to mangle declaration nodes. Special logic wired
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// into the code generator will display the mangled name if it's
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// present (and for AST_SymbolRef-s it'll use the mangled name of
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// the AST_SymbolDeclaration that it points to).
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var lname = -1;
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var tw = new TreeWalker(function(node, descend){
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if (node instanceof AST_LabeledStatement) {
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// lname is incremented when we get to the AST_Label
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var save_nesting = lname;
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descend();
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lname = save_nesting;
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return true; // don't descend again in TreeWalker
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}
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if (node instanceof AST_Scope) {
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var a = node.variables;
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for (var i in a) if (HOP(a, i)) {
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a[i].mangle();
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}
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return;
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}
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if (node instanceof AST_Label) {
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var name;
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do name = base54(++lname); while (!is_identifier(name));
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node.mangled_name = name;
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return;
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}
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});
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this.walk(tw);
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});
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