added mangler and other stuff

lib/scope.js

@@ -21,18 +21,20 @@ AST_Scope.DEFMETHOD("figure_out_scope", function(){
                 s.uses_with = true;
             return;
         }
-        if (node instanceof AST_SymbolDeclaration && !scope.parent_scope) {
-            node.global = true;
-        }
-        if (node instanceof AST_SymbolVar) {
-            scope.def_variable(node);
-        }
-        else if (node instanceof AST_SymbolLambda) {
+        if (node instanceof AST_SymbolLambda) {
             scope.def_function(node);
         }
         else if (node instanceof AST_SymbolDefun) {
+            // 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.
             scope.parent_scope.def_function(node);
         }
+        else if (node instanceof AST_SymbolVar) {
+            scope.def_variable(node);
+        }
         else if (node instanceof AST_Label) {
             scope.def_label(node);
         }
@@ -58,19 +60,72 @@ AST_Scope.DEFMETHOD("figure_out_scope", function(){
         }
         else if (node instanceof AST_SymbolRef) {
             var sym = node.scope.find_variable(node);
+            node.reference(sym);
             if (!sym) {
                 if (node.name == "eval") {
                     for (var s = scope; s; s = s.parent_scope)
                         s.uses_eval = true;
                 }
-            } else {
-                node.reference(sym);
             }
         }
     });
     this.walk(tw);
 });
 
+AST_Scope.DEFMETHOD("scope_warnings", function(options){
+    options = defaults(options, {
+        undeclared       : false,
+        assign_to_global : true
+    });
+    var tw = new TreeWalker(function(node){
+        if (options.undeclared
+            && node instanceof AST_SymbolRef
+            && node.undeclared)
+        {
+            // XXX: this also warns about JS standard names,
+            // i.e. Object, Array, parseInt etc.  Should add a list of
+            // exceptions.
+            AST_Node.warn("Undeclared symbol: {name} [{line},{col}]", {
+                name: node.name,
+                line: node.start.line,
+                col: node.start.col
+            });
+        }
+        if (options.assign_to_global
+            && node instanceof AST_Assign
+            && node.left instanceof AST_SymbolRef
+            && (node.left.undeclared
+                || (node.left.symbol.global
+                    && node.left.scope !== node.left.symbol.scope)))
+        {
+            AST_Node.warn("{msg}: {name} [{line},{col}]", {
+                msg: node.left.undeclared ? "Accidental global?" : "Assignment to global",
+                name: node.left.name,
+                line: node.start.line,
+                col: node.start.col
+            });
+        }
+    });
+    this.walk(tw);
+});
+
+AST_SymbolRef.DEFMETHOD("reference", function(symbol) {
+    if (symbol) {
+        this.symbol = symbol;
+        var origin = symbol.scope;
+        symbol.references.push(this);
+        for (var s = this.scope; s; s = s.parent_scope) {
+            push_uniq(s.enclosed, symbol);
+            if (s === origin) break;
+        }
+    } else {
+        this.undeclared = true;
+        for (var s = this.scope; s; s = s.parent_scope) {
+            push_uniq(s.enclosed, this);
+        }
+    }
+});
+
 AST_Scope.DEFMETHOD("find_variable", function(name){
     if (name instanceof AST_Symbol) name = name.name;
     return this.variables[name] ||
@@ -90,6 +145,7 @@ AST_Scope.DEFMETHOD("def_function", function(symbol){
 });
 
 AST_Scope.DEFMETHOD("def_variable", function(symbol){
+    symbol.global = !this.parent_scope;
     this.variables[symbol.name] = symbol;
     delete this.functions[symbol.name];
     symbol.scope = this;
@@ -99,3 +155,52 @@ AST_Scope.DEFMETHOD("def_label", function(symbol){
     this.labels[symbol.name] = symbol;
     symbol.scope = this;
 });
+
+AST_Scope.DEFMETHOD("next_mangled", function(for_label){
+    var ext = this.enclosed, n = ext.length;
+    out: for (;;) {
+        var m = base54(for_label
+                       ? (++this.lname)
+                       : (++this.cname));
+
+        if (!is_identifier(m)) continue; // skip over "do"
+
+        // labels are easy, since they can't be referenced from nested
+        // scopes.  XXX: not sure that will be the case when the `let`
+        // keyword is to be supported.
+        if (for_label) return m;
+
+        // if it's for functions or variables, we must ensure that the
+        // mangled name does not shadow a name from some parent scope
+        // that is referenced in this or in inner scopes.
+        for (var i = n; --i >= 0;) {
+            var sym = ext[i];
+            var name = sym.mangled_name || sym.name;
+            if (m == name) continue out;
+        }
+
+        return m;
+    }
+});
+
+AST_SymbolDeclaration.DEFMETHOD("mangle", function(){
+    if (!this.global)
+        this.mangled_name = this.scope.next_mangled(false);
+});
+
+AST_Label.DEFMETHOD("mangle", function(){
+    this.mangled_name = this.scope.next_mangled(true);
+});
+
+AST_Scope.DEFMETHOD("mangle_names", function(){
+    var tw = new TreeWalker(function(node){
+        // We only need to mangle declarations.  Special logic wired
+        // into the code generator will display the mangled name if
+        // it's present (and for AST_SymbolRef-s it'll use the mangled
+        // name of the AST_SymbolDeclaration that it points to).
+        if (node instanceof AST_SymbolDeclaration) {
+            node.mangle();
+        }
+    });
+    this.walk(tw);
+});