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consolidate & enhance unused (#2439)

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- defer declaration removal in `collapse_vars`
- account for `AST_SymbolFunarg` in deduplication
- private accounting for `collapse_vars`
- avoid issues with identity reference due to deep cloning

fixes #2437
This commit is contained in:
Alex Lam S.L
2017-11-06 14:25:10 +08:00
committed by GitHub
parent 2c2fd89e34
commit 6c45101870
4 changed files with 145 additions and 76 deletions
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52
lib/compress.js
View File

@@ -788,6 +788,14 @@ merge(Compressor.prototype, {
|| compressor.option("unsafe") && global_names(this.name); || compressor.option("unsafe") && global_names(this.name);
}); });
function drop_decl(def) {
def._eliminiated = (def._eliminiated || 0) + 1;
if (def.orig.length == def._eliminiated) {
def.scope.functions.del(def.name);
def.scope.variables.del(def.name);
}
}
function tighten_body(statements, compressor) { function tighten_body(statements, compressor) {
var CHANGED, max_iter = 10; var CHANGED, max_iter = 10;
do { do {
@@ -1000,7 +1008,8 @@ merge(Compressor.prototype, {
function get_lhs(expr) { function get_lhs(expr) {
if (expr instanceof AST_VarDef) { if (expr instanceof AST_VarDef) {
var def = expr.name.definition(); var def = expr.name.definition();
if (def.orig.length > 1 && !(expr.name instanceof AST_SymbolFunarg) if (def.orig.length - (def._eliminiated || 0) > 1
&& !(expr.name instanceof AST_SymbolFunarg)
|| def.references.length == 1 && !compressor.exposed(def)) { || def.references.length == 1 && !compressor.exposed(def)) {
return make_node(AST_SymbolRef, expr.name, expr.name); return make_node(AST_SymbolRef, expr.name, expr.name);
} }
@@ -1009,6 +1018,10 @@ merge(Compressor.prototype, {
} }
} }
function get_rvalue(expr) {
return expr[expr instanceof AST_Assign ? "right" : "value"];
}
function get_lvalues(expr) { function get_lvalues(expr) {
var lvalues = Object.create(null); var lvalues = Object.create(null);
if (expr instanceof AST_Unary) return lvalues; if (expr instanceof AST_Unary) return lvalues;
@@ -1019,7 +1032,7 @@ merge(Compressor.prototype, {
lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent()); lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent());
} }
}); });
expr[expr instanceof AST_Assign ? "right" : "value"].walk(tw); get_rvalue(expr).walk(tw);
return lvalues; return lvalues;
} }
@@ -1043,7 +1056,9 @@ merge(Compressor.prototype, {
if (node === expr) { if (node === expr) {
found = true; found = true;
if (node instanceof AST_VarDef) { if (node instanceof AST_VarDef) {
remove(node.name.definition().orig, node.name); drop_decl(node.name.definition());
node.value = null;
return node;
} }
return in_list ? MAP.skip : null; return in_list ? MAP.skip : null;
} }
@@ -1052,16 +1067,13 @@ merge(Compressor.prototype, {
case 0: return null; case 0: return null;
case 1: return node.expressions[0]; case 1: return node.expressions[0];
} }
if (node instanceof AST_Definitions && node.definitions.length == 0 if (node instanceof AST_SimpleStatement && !node.body) return null;
|| node instanceof AST_SimpleStatement && !node.body) {
return null;
}
})); }));
} }
function value_has_side_effects(expr) { function value_has_side_effects(expr) {
if (expr instanceof AST_Unary) return false; if (expr instanceof AST_Unary) return false;
return expr[expr instanceof AST_Assign ? "right" : "value"].has_side_effects(compressor); return get_rvalue(expr).has_side_effects(compressor);
} }
function references_in_scope(def) { function references_in_scope(def) {
@@ -2303,7 +2315,7 @@ merge(Compressor.prototype, {
// this scope (not in nested scopes). // this scope (not in nested scopes).
var scope = this; var scope = this;
var tw = new TreeWalker(function(node, descend){ var tw = new TreeWalker(function(node, descend){
if (node !== self) { if (node === self) return;
if (node instanceof AST_Defun) { if (node instanceof AST_Defun) {
if (!drop_funcs && scope === self) { if (!drop_funcs && scope === self) {
var node_def = node.name.definition(); var node_def = node.name.definition();
@@ -2315,6 +2327,9 @@ merge(Compressor.prototype, {
initializations.add(node.name.name, node); initializations.add(node.name.name, node);
return true; // don't go in nested scopes return true; // don't go in nested scopes
} }
if (node instanceof AST_SymbolFunarg && scope === self) {
var_defs_by_id.add(node.definition().id, node);
}
if (node instanceof AST_Definitions && scope === self) { if (node instanceof AST_Definitions && scope === self) {
node.definitions.forEach(function(def){ node.definitions.forEach(function(def){
var node_def = def.name.definition(); var node_def = def.name.definition();
@@ -2358,7 +2373,6 @@ merge(Compressor.prototype, {
scope = save_scope; scope = save_scope;
return true; return true;
} }
}
}); });
self.walk(tw); self.walk(tw);
// pass 2: for every used symbol we need to walk its // pass 2: for every used symbol we need to walk its
@@ -2415,7 +2429,7 @@ merge(Compressor.prototype, {
var def = node.name.definition(); var def = node.name.definition();
if (!(def.id in in_use_ids)) { if (!(def.id in in_use_ids)) {
compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name)); compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
drop_decl(def, node.name); drop_decl(def);
return make_node(AST_EmptyStatement, node); return make_node(AST_EmptyStatement, node);
} }
return node; return node;
@@ -2437,7 +2451,7 @@ merge(Compressor.prototype, {
if (var_defs.length > 1 && !def.value) { if (var_defs.length > 1 && !def.value) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name)); compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
remove(var_defs, def); remove(var_defs, def);
drop_decl(sym, def.name); drop_decl(sym);
return; return;
} }
} }
@@ -2470,7 +2484,7 @@ merge(Compressor.prototype, {
} else { } else {
compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name)); compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
} }
drop_decl(sym, def.name); drop_decl(sym);
} }
}); });
if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) { if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) {
@@ -2479,7 +2493,7 @@ merge(Compressor.prototype, {
var def = tail.pop(); var def = tail.pop();
compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name)); compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name));
remove(var_defs, def); remove(var_defs, def);
drop_decl(def.name.definition(), def.name); drop_decl(def.name.definition());
side_effects.unshift(make_node(AST_Assign, def, { side_effects.unshift(make_node(AST_Assign, def, {
operator: "=", operator: "=",
left: make_node(AST_SymbolRef, def.name, def.name), left: make_node(AST_SymbolRef, def.name, def.name),
@@ -2561,14 +2575,6 @@ merge(Compressor.prototype, {
col : sym.start.col col : sym.start.col
}; };
} }
function drop_decl(def, decl) {
remove(def.orig, decl);
if (!def.orig.length) {
def.scope.functions.del(def.name);
def.scope.variables.del(def.name);
}
}
} }
); );
self.transform(tt); self.transform(tt);
@@ -3288,7 +3294,7 @@ merge(Compressor.prototype, {
})); }));
if (reduce_vars) name.definition().fixed = false; if (reduce_vars) name.definition().fixed = false;
} }
remove(def.name.definition().orig, def.name); drop_decl(def.name.definition());
return a; return a;
}, []); }, []);
if (assignments.length == 0) return null; if (assignments.length == 0) return null;

64
test/compress/collapse_vars.js
View File

@@ -1388,6 +1388,7 @@ issue_1605_1: {
options = { options = {
collapse_vars: true, collapse_vars: true,
toplevel: false, toplevel: false,
unused: true,
} }
input: { input: {
function foo(x) { function foo(x) {
@@ -1410,6 +1411,7 @@ issue_1605_2: {
options = { options = {
collapse_vars: true, collapse_vars: true,
toplevel: "vars", toplevel: "vars",
unused: true,
} }
input: { input: {
function foo(x) { function foo(x) {
@@ -1537,6 +1539,7 @@ issue_1631_3: {
var_side_effects_1: { var_side_effects_1: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var print = console.log.bind(console); var print = console.log.bind(console);
@@ -1559,6 +1562,7 @@ var_side_effects_1: {
var_side_effects_2: { var_side_effects_2: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var print = console.log.bind(console); var print = console.log.bind(console);
@@ -1584,6 +1588,7 @@ var_side_effects_3: {
collapse_vars: true, collapse_vars: true,
pure_getters: true, pure_getters: true,
unsafe: true, unsafe: true,
unused: true,
} }
input: { input: {
var print = console.log.bind(console); var print = console.log.bind(console);
@@ -1659,6 +1664,7 @@ iife_2: {
}(foo); }(foo);
} }
expect: { expect: {
var foo;
!function(x) { !function(x) {
console.log(x); console.log(x);
}(bar()); }(bar());
@@ -1945,6 +1951,7 @@ ref_scope: {
chained_1: { chained_1: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var a = 2; var a = 2;
@@ -1961,6 +1968,7 @@ chained_1: {
chained_2: { chained_2: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var a; var a;
@@ -2061,6 +2069,7 @@ inner_lvalues: {
double_def: { double_def: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var a = x, a = a && y; var a = x, a = a && y;
@@ -2075,6 +2084,7 @@ double_def: {
toplevel_single_reference: { toplevel_single_reference: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
var a; var a;
@@ -2084,10 +2094,11 @@ toplevel_single_reference: {
} }
} }
expect: { expect: {
for (var b in x) {
var a; var a;
for (var b in x)
b(a = b); b(a = b);
} }
}
} }
unused_orig: { unused_orig: {
@@ -2889,6 +2900,7 @@ pure_getters_chain: {
options = { options = {
collapse_vars: true, collapse_vars: true,
pure_getters: true, pure_getters: true,
unused: true,
} }
input: { input: {
function o(t, r) { function o(t, r) {
@@ -2909,6 +2921,7 @@ pure_getters_chain: {
conditional_1: { conditional_1: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
function f(a, b) { function f(a, b) {
@@ -2933,6 +2946,7 @@ conditional_1: {
conditional_2: { conditional_2: {
options = { options = {
collapse_vars: true, collapse_vars: true,
unused: true,
} }
input: { input: {
function f(a, b) { function f(a, b) {
@@ -3015,3 +3029,51 @@ issue_2425_3: {
} }
expect_stdout: "15" expect_stdout: "15"
} }
issue_2437: {
options = {
collapse_vars: true,
conditionals: true,
inline: true,
join_vars: true,
reduce_vars: true,
side_effects: true,
sequences: true,
toplevel: true,
unused: true,
}
input: {
function foo() {
bar();
}
function bar() {
if (xhrDesc) {
var req = new XMLHttpRequest();
var result = !!req.onreadystatechange;
Object.defineProperty(XMLHttpRequest.prototype, 'onreadystatechange', xhrDesc || {});
return result;
}
else {
var req = new XMLHttpRequest();
var detectFunc = function () { };
req.onreadystatechange = detectFunc;
var result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
req.onreadystatechange = null;
return result;
}
}
foo();
}
expect: {
!function() {
if (xhrDesc)
return result = !!(req = new XMLHttpRequest()).onreadystatechange,
Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {}),
result;
var req = new XMLHttpRequest(), detectFunc = function() {};
req.onreadystatechange = detectFunc;
var result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
req.onreadystatechange = null;
}();
}
}

1
test/compress/issue-973.js
View File

@@ -51,6 +51,7 @@ this_binding_collapse_vars: {
options = { options = {
collapse_vars: true, collapse_vars: true,
toplevel: true, toplevel: true,
unused: true,
}; };
input: { input: {
var c = a; c(); var c = a; c();

12
test/compress/reduce_vars.js
View File

@@ -2131,14 +2131,13 @@ redefine_farg_1: {
} }
expect: { expect: {
function f(a) { function f(a) {
var a;
return typeof a; return typeof a;
} }
function g() { function g() {
return"number"; return "number";
} }
function h(a, b) { function h(a, b) {
var a = b; a = b;
return typeof a; return typeof a;
} }
console.log(f([]), g([]), h([])); console.log(f([]), g([]), h([]));
@@ -2173,10 +2172,9 @@ redefine_farg_2: {
} }
expect: { expect: {
console.log(function(a) { console.log(function(a) {
var a;
return typeof a; return typeof a;
}([]), "number",function(a, b) { }([]), "number",function(a, b) {
var a = b; a = b;
return typeof a; return typeof a;
}([])); }([]));
} }
@@ -2185,11 +2183,13 @@ redefine_farg_2: {
redefine_farg_3: { redefine_farg_3: {
options = { options = {
cascade: true,
evaluate: true, evaluate: true,
inline: true, inline: true,
keep_fargs: false, keep_fargs: false,
passes: 3, passes: 2,
reduce_vars: true, reduce_vars: true,
sequences: true,
side_effects: true, side_effects: true,
toplevel: true, toplevel: true,
unused: true, unused: true,