enforce toplevel on other compress options (#1855)

Respect "funcs" and "vars" properly.

fixes #1850

lib/compress.js

@@ -109,6 +109,14 @@ function Compressor(options, false_by_default) {
             return top_retain.indexOf(def.name) >= 0;
         };
     }
+    var toplevel = this.options["toplevel"];
+    if (typeof toplevel == "string") {
+        this.toplevel.funcs = /funcs/.test(toplevel);
+        this.toplevel.vars = /vars/.test(toplevel);
+    } else {
+        this.toplevel = toplevel ? return_true : return_false;
+        this.toplevel.funcs = this.toplevel.vars = toplevel;
+    }
     var sequences = this.options["sequences"];
     this.sequences_limit = sequences == 1 ? 800 : sequences | 0;
     this.warnings_produced = {};
@@ -117,6 +125,12 @@ function Compressor(options, false_by_default) {
 Compressor.prototype = new TreeTransformer;
 merge(Compressor.prototype, {
     option: function(key) { return this.options[key] },
+    toplevel: function(def) {
+        for (var i = 0, len = def.orig.length; i < len; i++)
+            if (!this.toplevel[def.orig[i] instanceof AST_SymbolDefun ? "funcs" : "vars"])
+                return false;
+        return true;
+    },
     compress: function(node) {
         if (this.option("expression")) {
             node.process_expression(true);
@@ -249,7 +263,6 @@ merge(Compressor.prototype, {
 
     AST_Node.DEFMETHOD("reset_opt_flags", function(compressor, rescan) {
         var reduce_vars = rescan && compressor.option("reduce_vars");
-        var toplevel = compressor.option("toplevel");
         var safe_ids = Object.create(null);
         var suppressor = new TreeWalker(function(node) {
             if (node instanceof AST_Symbol) {
@@ -310,7 +323,7 @@ merge(Compressor.prototype, {
                 }
                 if (node instanceof AST_Defun) {
                     var d = node.name.definition();
-                    if (!toplevel && d.global || safe_to_read(d)) {
+                    if (d.global && !compressor.toplevel(d) || safe_to_read(d)) {
                         d.fixed = false;
                     } else {
                         d.fixed = node;
@@ -469,7 +482,7 @@ merge(Compressor.prototype, {
         }
 
         function reset_def(def) {
-            if (toplevel || !def.global || def.orig[0] instanceof AST_SymbolConst) {
+            if (!def.global || def.orig[0] instanceof AST_SymbolConst || compressor.toplevel(def)) {
                 def.fixed = undefined;
             } else {
                 def.fixed = false;
@@ -643,7 +656,6 @@ merge(Compressor.prototype, {
             // in the statement with the var value and then erase the var definition.
 
             var scope = compressor.find_parent(AST_Scope);
-            var toplevel = compressor.option("toplevel");
             var stat_index;
             var prev_stat_index;
             var def_stat_index;
@@ -694,7 +706,8 @@ merge(Compressor.prototype, {
                     // Only interested in cases with just one reference to the variable.
                     var def = var_decl.name.definition();
                     if (def.references.length !== 1
-                        || var_name == "arguments" || (!toplevel && def.global)) {
+                        || var_name == "arguments"
+                        || def.global && !compressor.toplevel(def)) {
                         side_effects_encountered = true;
                         continue;
                     }
@@ -1825,19 +1838,14 @@ merge(Compressor.prototype, {
     });
 
     AST_Scope.DEFMETHOD("drop_unused", function(compressor){
+        if (!compressor.option("unused")) return;
+        if (compressor.has_directive("use asm")) return;
         var self = this;
-        if (compressor.has_directive("use asm")) return self;
+        if (self.uses_eval || self.uses_with) return;
-        var toplevel = compressor.option("toplevel");
+        var drop_funcs = !(self instanceof AST_Toplevel) || compressor.toplevel.funcs;
-        if (compressor.option("unused")
+        var drop_vars = !(self instanceof AST_Toplevel) || compressor.toplevel.vars;
-            && (!(self instanceof AST_Toplevel) || toplevel)
+        if (!drop_funcs && !drop_vars) return;
-            && !self.uses_eval
-            && !self.uses_with) {
         var assign_as_unused = !/keep_assign/.test(compressor.option("unused"));
-            var drop_funcs = /funcs/.test(toplevel);
-            var drop_vars = /vars/.test(toplevel);
-            if (!(self instanceof AST_Toplevel) || toplevel == true) {
-                drop_funcs = drop_vars = true;
-            }
         var in_use = [];
         var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use
         if (self instanceof AST_Toplevel && compressor.top_retain) {
@@ -2107,7 +2115,6 @@ merge(Compressor.prototype, {
             }
         );
         self.transform(tt);
-        }
     });
 
     AST_Scope.DEFMETHOD("hoist_declarations", function(compressor){
@@ -3683,7 +3690,7 @@ merge(Compressor.prototype, {
                         }
                         var name = d.name.length;
                         var overhead = 0;
-                        if (compressor.option("unused") && (!d.global || compressor.option("toplevel"))) {
+                        if (compressor.option("unused") && (!d.global || compressor.toplevel(d))) {
                             overhead = (name + 2 + value) / d.references.length;
                         }
                         d.should_replace = value <= name + overhead ? fn : false;

test/compress/reduce_vars.js

@@ -2327,3 +2327,93 @@ iife_assign: {
     }
     expect_stdout: "1"
 }
+
+issue_1850_1: {
+    options = {
+        reduce_vars: true,
+        toplevel: false,
+        unused: true,
+    }
+    input: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect_stdout: true
+}
+
+issue_1850_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: "funcs",
+        unused: true,
+    }
+    input: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect: {
+        var a = 1;
+        (function() {
+            console.log(a, a, a);
+        })();
+    }
+    expect_stdout: true
+}
+
+issue_1850_3: {
+    options = {
+        reduce_vars: true,
+        toplevel: "vars",
+        unused: true,
+    }
+    input: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect_stdout: true
+}
+
+issue_1850_4: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            console.log(a, a, a);
+        }
+        var a = 1;
+        f();
+    }
+    expect: {
+        var a = 1;
+        (function() {
+            console.log(a, a, a);
+        })();
+    }
+    expect_stdout: true
+}