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enforce toplevel on other compress options (#1855)

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Respect "funcs" and "vars" properly.

fixes #1850
This commit is contained in:
Alex Lam S.L
2017-04-30 22:52:36 +08:00
committed by GitHub
parent bbb5f2a89c
commit 2cb55b2ad0
2 changed files with 362 additions and 265 deletions
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537
lib/compress.js
View File

@@ -109,6 +109,14 @@ function Compressor(options, false_by_default) {
return top_retain.indexOf(def.name) >= 0; 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"]; var sequences = this.options["sequences"];
this.sequences_limit = sequences == 1 ? 800 : sequences | 0; this.sequences_limit = sequences == 1 ? 800 : sequences | 0;
this.warnings_produced = {}; this.warnings_produced = {};
@@ -117,6 +125,12 @@ function Compressor(options, false_by_default) {
Compressor.prototype = new TreeTransformer; Compressor.prototype = new TreeTransformer;
merge(Compressor.prototype, { merge(Compressor.prototype, {
option: function(key) { return this.options[key] }, 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) { compress: function(node) {
if (this.option("expression")) { if (this.option("expression")) {
node.process_expression(true); node.process_expression(true);
@@ -249,7 +263,6 @@ merge(Compressor.prototype, {
AST_Node.DEFMETHOD("reset_opt_flags", function(compressor, rescan) { AST_Node.DEFMETHOD("reset_opt_flags", function(compressor, rescan) {
var reduce_vars = rescan && compressor.option("reduce_vars"); var reduce_vars = rescan && compressor.option("reduce_vars");
var toplevel = compressor.option("toplevel");
var safe_ids = Object.create(null); var safe_ids = Object.create(null);
var suppressor = new TreeWalker(function(node) { var suppressor = new TreeWalker(function(node) {
if (node instanceof AST_Symbol) { if (node instanceof AST_Symbol) {
@@ -310,7 +323,7 @@ merge(Compressor.prototype, {
} }
if (node instanceof AST_Defun) { if (node instanceof AST_Defun) {
var d = node.name.definition(); 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; d.fixed = false;
} else { } else {
d.fixed = node; d.fixed = node;
@@ -469,7 +482,7 @@ merge(Compressor.prototype, {
} }
function reset_def(def) { 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; def.fixed = undefined;
} else { } else {
def.fixed = false; def.fixed = false;
@@ -643,7 +656,6 @@ merge(Compressor.prototype, {
// in the statement with the var value and then erase the var definition. // in the statement with the var value and then erase the var definition.
var scope = compressor.find_parent(AST_Scope); var scope = compressor.find_parent(AST_Scope);
var toplevel = compressor.option("toplevel");
var stat_index; var stat_index;
var prev_stat_index; var prev_stat_index;
var def_stat_index; var def_stat_index;
@@ -694,7 +706,8 @@ merge(Compressor.prototype, {
// Only interested in cases with just one reference to the variable. // Only interested in cases with just one reference to the variable.
var def = var_decl.name.definition(); var def = var_decl.name.definition();
if (def.references.length !== 1 if (def.references.length !== 1
|| var_name == "arguments" || (!toplevel && def.global)) { || var_name == "arguments"
|| def.global && !compressor.toplevel(def)) {
side_effects_encountered = true; side_effects_encountered = true;
continue; continue;
} }
@@ -1825,289 +1838,283 @@ merge(Compressor.prototype, {
}); });
AST_Scope.DEFMETHOD("drop_unused", function(compressor){ AST_Scope.DEFMETHOD("drop_unused", function(compressor){
if (!compressor.option("unused")) return;
if (compressor.has_directive("use asm")) return;
var self = this; 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 var assign_as_unused = !/keep_assign/.test(compressor.option("unused"));
&& !self.uses_with) { var in_use = [];
var assign_as_unused = !/keep_assign/.test(compressor.option("unused")); var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use
var drop_funcs = /funcs/.test(toplevel); if (self instanceof AST_Toplevel && compressor.top_retain) {
var drop_vars = /vars/.test(toplevel); self.variables.each(function(def) {
if (!(self instanceof AST_Toplevel) || toplevel == true) { if (compressor.top_retain(def) && !(def.id in in_use_ids)) {
drop_funcs = drop_vars = true; in_use_ids[def.id] = true;
} in_use.push(def);
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) { }
self.variables.each(function(def) { var var_defs_by_id = new Dictionary();
if (compressor.top_retain(def) && !(def.id in in_use_ids)) { var initializations = new Dictionary();
in_use_ids[def.id] = true; // pass 1: find out which symbols are directly used in
in_use.push(def); // this scope (not in nested scopes).
var scope = this;
var tw = new TreeWalker(function(node, descend){
if (node !== self) {
if (node instanceof AST_Defun) {
if (!drop_funcs && scope === self) {
var node_def = node.name.definition();
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
}
} }
}); initializations.add(node.name.name, node);
} return true; // don't go in nested scopes
var var_defs_by_id = new Dictionary(); }
var initializations = new Dictionary(); if (node instanceof AST_Definitions && scope === self) {
// pass 1: find out which symbols are directly used in node.definitions.forEach(function(def){
// this scope (not in nested scopes). var node_def = def.name.definition();
var scope = this; if (def.name instanceof AST_SymbolVar) {
var tw = new TreeWalker(function(node, descend){ var_defs_by_id.add(node_def.id, def);
if (node !== self) { }
if (node instanceof AST_Defun) { if (!drop_vars) {
if (!drop_funcs && scope === self) {
var node_def = node.name.definition();
if (!(node_def.id in in_use_ids)) { if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true; in_use_ids[node_def.id] = true;
in_use.push(node_def); in_use.push(node_def);
} }
} }
initializations.add(node.name.name, node); if (def.value) {
return true; // don't go in nested scopes initializations.add(def.name.name, def.value);
} if (def.value.has_side_effects(compressor)) {
if (node instanceof AST_Definitions && scope === self) { def.value.walk(tw);
node.definitions.forEach(function(def){
var node_def = def.name.definition();
if (def.name instanceof AST_SymbolVar) {
var_defs_by_id.add(node_def.id, def);
} }
if (!drop_vars) { }
if (!(node_def.id in in_use_ids)) { });
in_use_ids[node_def.id] = true; return true;
in_use.push(node_def); }
if (assign_as_unused
&& node instanceof AST_Assign
&& node.operator == "="
&& node.left instanceof AST_SymbolRef
&& scope === self) {
node.right.walk(tw);
return true;
}
if (node instanceof AST_SymbolRef) {
var node_def = node.definition();
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
}
return true;
}
if (node instanceof AST_Scope) {
var save_scope = scope;
scope = node;
descend();
scope = save_scope;
return true;
}
}
});
self.walk(tw);
// pass 2: for every used symbol we need to walk its
// initialization code to figure out if it uses other
// symbols (that may not be in_use).
for (var i = 0; i < in_use.length; ++i) {
in_use[i].orig.forEach(function(decl){
// undeclared globals will be instanceof AST_SymbolRef
var init = initializations.get(decl.name);
if (init) init.forEach(function(init){
var tw = new TreeWalker(function(node){
if (node instanceof AST_SymbolRef) {
var node_def = node.definition();
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
}
}
});
init.walk(tw);
});
});
}
// pass 3: we should drop declarations not in_use
var tt = new TreeTransformer(
function before(node, descend, in_list) {
if (node instanceof AST_Function
&& node.name
&& !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_Lambda && !(node instanceof AST_Accessor)) {
var trim = !compressor.option("keep_fargs");
for (var a = node.argnames, i = a.length; --i >= 0;) {
var sym = a[i];
if (!(sym.definition().id in in_use_ids)) {
sym.__unused = true;
if (trim) {
a.pop();
compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym));
}
}
else {
trim = false;
}
}
}
if (drop_funcs && node instanceof AST_Defun && node !== self) {
if (!(node.name.definition().id in in_use_ids)) {
compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
return make_node(AST_EmptyStatement, node);
}
return node;
}
if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn && tt.parent().init === node)) {
// place uninitialized names at the start
var body = [], head = [], tail = [];
// for unused names whose initialization has
// side effects, we can cascade the init. code
// into the next one, or next statement.
var side_effects = [];
node.definitions.forEach(function(def) {
if (def.value) def.value = def.value.transform(tt);
var sym = def.name.definition();
if (sym.id in in_use_ids) {
if (def.name instanceof AST_SymbolVar) {
var var_defs = var_defs_by_id.get(sym.id);
if (var_defs.length > 1 && !def.value) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
var_defs.splice(var_defs.indexOf(def), 1);
return;
} }
} }
if (def.value) { if (def.value) {
initializations.add(def.name.name, def.value); if (side_effects.length > 0) {
if (def.value.has_side_effects(compressor)) { if (tail.length > 0) {
def.value.walk(tw); merge_sequence(side_effects, def.value);
} def.value = make_sequence(def.value, side_effects);
} } else {
}); body.push(make_node(AST_SimpleStatement, node, {
return true; body: make_sequence(node, side_effects)
} }));
if (assign_as_unused
&& node instanceof AST_Assign
&& node.operator == "="
&& node.left instanceof AST_SymbolRef
&& scope === self) {
node.right.walk(tw);
return true;
}
if (node instanceof AST_SymbolRef) {
var node_def = node.definition();
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
}
return true;
}
if (node instanceof AST_Scope) {
var save_scope = scope;
scope = node;
descend();
scope = save_scope;
return true;
}
}
});
self.walk(tw);
// pass 2: for every used symbol we need to walk its
// initialization code to figure out if it uses other
// symbols (that may not be in_use).
for (var i = 0; i < in_use.length; ++i) {
in_use[i].orig.forEach(function(decl){
// undeclared globals will be instanceof AST_SymbolRef
var init = initializations.get(decl.name);
if (init) init.forEach(function(init){
var tw = new TreeWalker(function(node){
if (node instanceof AST_SymbolRef) {
var node_def = node.definition();
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
in_use.push(node_def);
}
}
});
init.walk(tw);
});
});
}
// pass 3: we should drop declarations not in_use
var tt = new TreeTransformer(
function before(node, descend, in_list) {
if (node instanceof AST_Function
&& node.name
&& !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_Lambda && !(node instanceof AST_Accessor)) {
var trim = !compressor.option("keep_fargs");
for (var a = node.argnames, i = a.length; --i >= 0;) {
var sym = a[i];
if (!(sym.definition().id in in_use_ids)) {
sym.__unused = true;
if (trim) {
a.pop();
compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym));
}
}
else {
trim = false;
}
}
}
if (drop_funcs && node instanceof AST_Defun && node !== self) {
if (!(node.name.definition().id in in_use_ids)) {
compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
return make_node(AST_EmptyStatement, node);
}
return node;
}
if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn && tt.parent().init === node)) {
// place uninitialized names at the start
var body = [], head = [], tail = [];
// for unused names whose initialization has
// side effects, we can cascade the init. code
// into the next one, or next statement.
var side_effects = [];
node.definitions.forEach(function(def) {
if (def.value) def.value = def.value.transform(tt);
var sym = def.name.definition();
if (sym.id in in_use_ids) {
if (def.name instanceof AST_SymbolVar) {
var var_defs = var_defs_by_id.get(sym.id);
if (var_defs.length > 1 && !def.value) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
var_defs.splice(var_defs.indexOf(def), 1);
return;
} }
side_effects = [];
} }
if (def.value) { tail.push(def);
if (side_effects.length > 0) {
if (tail.length > 0) {
merge_sequence(side_effects, def.value);
def.value = make_sequence(def.value, side_effects);
} else {
body.push(make_node(AST_SimpleStatement, node, {
body: make_sequence(node, side_effects)
}));
}
side_effects = [];
}
tail.push(def);
} else {
head.push(def);
}
} else if (sym.orig[0] instanceof AST_SymbolCatch) {
var value = def.value && def.value.drop_side_effect_free(compressor);
if (value) merge_sequence(side_effects, value);
def.value = null;
head.push(def);
} else { } else {
var value = def.value && def.value.drop_side_effect_free(compressor); head.push(def);
if (value) {
compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
merge_sequence(side_effects, value);
} else {
compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
}
} }
}); } else if (sym.orig[0] instanceof AST_SymbolCatch) {
if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) { var value = def.value && def.value.drop_side_effect_free(compressor);
var var_defs = var_defs_by_id.get(tail[0].name.definition().id); if (value) merge_sequence(side_effects, value);
if (var_defs.length > 1) { def.value = null;
var def = tail.pop(); head.push(def);
compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name)); } else {
var_defs.splice(var_defs.indexOf(def), 1); var value = def.value && def.value.drop_side_effect_free(compressor);
side_effects.unshift(make_node(AST_Assign, def, { if (value) {
operator: "=", compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
left: make_node(AST_SymbolRef, def.name, def.name), merge_sequence(side_effects, value);
right: def.value } else {
})); compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
} }
} }
if (head.length > 0 || tail.length > 0) { });
node.definitions = head.concat(tail); if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) {
body.push(node); var var_defs = var_defs_by_id.get(tail[0].name.definition().id);
} if (var_defs.length > 1) {
if (side_effects.length > 0) { var def = tail.pop();
body.push(make_node(AST_SimpleStatement, node, { compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name));
body: make_sequence(node, side_effects) var_defs.splice(var_defs.indexOf(def), 1);
side_effects.unshift(make_node(AST_Assign, def, {
operator: "=",
left: make_node(AST_SymbolRef, def.name, def.name),
right: def.value
})); }));
} }
switch (body.length) {
case 0:
return in_list ? MAP.skip : make_node(AST_EmptyStatement, node);
case 1:
return body[0];
default:
return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
body: body
});
}
} }
if (drop_vars && assign_as_unused if (head.length > 0 || tail.length > 0) {
&& node instanceof AST_Assign node.definitions = head.concat(tail);
&& node.operator == "=" body.push(node);
&& node.left instanceof AST_SymbolRef) {
var def = node.left.definition();
if (!(def.id in in_use_ids)
&& self.variables.get(def.name) === def) {
return maintain_this_binding(tt.parent(), node, node.right.transform(tt));
}
} }
// certain combination of unused name + side effect leads to: if (side_effects.length > 0) {
// https://github.com/mishoo/UglifyJS2/issues/44 body.push(make_node(AST_SimpleStatement, node, {
// https://github.com/mishoo/UglifyJS2/issues/1830 body: make_sequence(node, side_effects)
// https://github.com/mishoo/UglifyJS2/issues/1838 }));
// that's an invalid AST.
// We fix it at this stage by moving the `var` outside the `for`.
if (node instanceof AST_For) {
descend(node, this);
if (node.init instanceof AST_BlockStatement) {
var block = node.init;
node.init = block.body.pop();
block.body.push(node);
return in_list ? MAP.splice(block.body) : block;
} else if (node.init instanceof AST_SimpleStatement) {
node.init = node.init.body;
} else if (is_empty(node.init)) {
node.init = null;
}
return node;
} }
if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) { switch (body.length) {
descend(node, this); case 0:
if (node.body instanceof AST_BlockStatement) { return in_list ? MAP.skip : make_node(AST_EmptyStatement, node);
var block = node.body; case 1:
node.body = block.body.pop(); return body[0];
block.body.push(node); default:
return in_list ? MAP.splice(block.body) : block; return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
} body: body
return node; });
}
if (node instanceof AST_Scope && node !== self)
return node;
function template(sym) {
return {
name : sym.name,
file : sym.start.file,
line : sym.start.line,
col : sym.start.col
};
} }
} }
); if (drop_vars && assign_as_unused
self.transform(tt); && node instanceof AST_Assign
} && node.operator == "="
&& node.left instanceof AST_SymbolRef) {
var def = node.left.definition();
if (!(def.id in in_use_ids)
&& self.variables.get(def.name) === def) {
return maintain_this_binding(tt.parent(), node, node.right.transform(tt));
}
}
// certain combination of unused name + side effect leads to:
// https://github.com/mishoo/UglifyJS2/issues/44
// https://github.com/mishoo/UglifyJS2/issues/1830
// https://github.com/mishoo/UglifyJS2/issues/1838
// that's an invalid AST.
// We fix it at this stage by moving the `var` outside the `for`.
if (node instanceof AST_For) {
descend(node, this);
if (node.init instanceof AST_BlockStatement) {
var block = node.init;
node.init = block.body.pop();
block.body.push(node);
return in_list ? MAP.splice(block.body) : block;
} else if (node.init instanceof AST_SimpleStatement) {
node.init = node.init.body;
} else if (is_empty(node.init)) {
node.init = null;
}
return node;
}
if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) {
descend(node, this);
if (node.body instanceof AST_BlockStatement) {
var block = node.body;
node.body = block.body.pop();
block.body.push(node);
return in_list ? MAP.splice(block.body) : block;
}
return node;
}
if (node instanceof AST_Scope && node !== self)
return node;
function template(sym) {
return {
name : sym.name,
file : sym.start.file,
line : sym.start.line,
col : sym.start.col
};
}
}
);
self.transform(tt);
}); });
AST_Scope.DEFMETHOD("hoist_declarations", function(compressor){ AST_Scope.DEFMETHOD("hoist_declarations", function(compressor){
@@ -3683,7 +3690,7 @@ merge(Compressor.prototype, {
} }
var name = d.name.length; var name = d.name.length;
var overhead = 0; 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; overhead = (name + 2 + value) / d.references.length;
} }
d.should_replace = value <= name + overhead ? fn : false; d.should_replace = value <= name + overhead ? fn : false;

90
test/compress/reduce_vars.js
View File

@@ -2327,3 +2327,93 @@ iife_assign: {
} }
expect_stdout: "1" 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
}