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transform function calls to IIFEs (#1560)

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- expose function body to call sites for potential optimisations
- suppress substitution of variable used within `AST_Defun`
This commit is contained in:
Alex Lam S.L
2017-03-07 15:37:52 +08:00
committed by GitHub
parent d787d70127
commit 8153b7bd8a
5 changed files with 284 additions and 29 deletions
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10
lib/ast.js
View File

@@ -91,7 +91,15 @@ var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos
}, null);
var AST_Node = DEFNODE("Node", "start end", {
clone: function() {
clone: function(deep) {
if (deep) {
var self = this.clone();
return self.transform(new TreeTransformer(function(node) {
if (node !== self) {
return node.clone(true);
}
}));
}
return new this.CTOR(this);
},
$documentation: "Base class of all AST nodes",

51
lib/compress.js
View File

@@ -245,7 +245,8 @@ merge(Compressor.prototype, {
if (node instanceof AST_SymbolRef) {
var d = node.definition();
d.references.push(node);
if (!d.fixed || isModified(node, 0) || !is_safe(d)) {
if (!d.fixed || !is_safe(d)
|| is_modified(node, 0, d.fixed instanceof AST_Lambda)) {
d.fixed = false;
}
}
@@ -261,6 +262,21 @@ merge(Compressor.prototype, {
d.fixed = false;
}
}
if (node instanceof AST_Defun) {
var d = node.name.definition();
if (!toplevel && d.global || is_safe(d)) {
d.fixed = false;
} else {
d.fixed = node;
mark_as_safe(d);
}
var save_ids = safe_ids;
safe_ids = [];
push();
descend();
safe_ids = save_ids;
return true;
}
var iife;
if (node instanceof AST_Function
&& (iife = tw.parent()) instanceof AST_Call
@@ -344,13 +360,13 @@ merge(Compressor.prototype, {
def.should_replace = undefined;
}
function isModified(node, level) {
function is_modified(node, level, func) {
var parent = tw.parent(level);
if (isLHS(node, parent)
|| parent instanceof AST_Call && parent.expression === node) {
|| !func && parent instanceof AST_Call && parent.expression === node) {
return true;
} else if (parent instanceof AST_PropAccess && parent.expression === node) {
return isModified(parent, level + 1);
return !func && is_modified(parent, level + 1);
}
}
});
@@ -1307,14 +1323,7 @@ merge(Compressor.prototype, {
def(AST_Statement, function(){
throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start));
});
// XXX: AST_Accessor and AST_Function both inherit from AST_Scope,
// which itself inherits from AST_Statement; however, they aren't
// really statements. This could bite in other places too. :-(
// Wish JS had multiple inheritance.
def(AST_Accessor, function(){
throw def;
});
def(AST_Function, function(){
def(AST_Lambda, function(){
throw def;
});
function ev(node, compressor) {
@@ -2590,6 +2599,24 @@ merge(Compressor.prototype, {
OPT(AST_Call, function(self, compressor){
var exp = self.expression;
if (compressor.option("reduce_vars")
&& exp instanceof AST_SymbolRef) {
var def = exp.definition();
if (def.fixed instanceof AST_Defun) {
def.fixed = make_node(AST_Function, def.fixed, def.fixed).clone(true);
}
if (def.fixed instanceof AST_Function) {
exp = def.fixed;
if (compressor.option("unused")
&& def.references.length == 1
&& compressor.find_parent(AST_Scope) === def.scope) {
if (!compressor.option("keep_fnames")) {
exp.name = null;
}
self.expression = exp;
}
}
}
if (compressor.option("unused")
&& exp instanceof AST_Function
&& !exp.uses_arguments

238
test/compress/reduce_vars.js
View File

@@ -744,12 +744,11 @@ toplevel_on_loops_1: {
while (x);
}
expect: {
function bar() {
console.log("bar:", --x);
}
var x = 3;
do
bar();
(function() {
console.log("bar:", --x);
})();
while (x);
}
}
@@ -800,10 +799,9 @@ toplevel_on_loops_2: {
while (x);
}
expect: {
function bar() {
for (;;) (function() {
console.log("bar:");
}
for (;;) bar();
})();
}
}
@@ -869,3 +867,229 @@ toplevel_off_loops_3: {
for (;x;) bar();
}
}
defun_reference: {
options = {
evaluate: true,
reduce_vars: true,
}
input: {
function f() {
function g() {
x();
return a;
}
var a = h();
var b = 2;
return a + b;
function h() {
y();
return b;
}
}
}
expect: {
function f() {
function g() {
x();
return a;
}
var a = h();
var b = 2;
return a + b;
function h() {
y();
return b;
}
}
}
}
defun_inline_1: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f() {
return g(2) + h();
function g(b) {
return b;
}
function h() {
return h();
}
}
}
expect: {
function f() {
return function(b) {
return b;
}(2) + h();
function h() {
return h();
}
}
}
}
defun_inline_2: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f() {
function g(b) {
return b;
}
function h() {
return h();
}
return g(2) + h();
}
}
expect: {
function f() {
function h() {
return h();
}
return function(b) {
return b;
}(2) + h();
}
}
}
defun_inline_3: {
options = {
evaluate: true,
passes: 2,
reduce_vars: true,
side_effects: true,
unused: true,
}
input: {
function f() {
return g(2);
function g(b) {
return b;
}
}
}
expect: {
function f() {
return 2;
}
}
}
defun_call: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f() {
return g() + h(1) - h(g(), 2, 3);
function g() {
return 4;
}
function h(a) {
return a;
}
}
}
expect: {
function f() {
return 4 + h(1) - h(4);
function h(a) {
return a;
}
}
}
}
defun_redefine: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f() {
function g() {
return 1;
}
function h() {
return 2;
}
g = function() {
return 3;
};
return g() + h();
}
}
expect: {
function f() {
function g() {
return 1;
}
g = function() {
return 3;
};
return g() + 2;
}
}
}
func_inline: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f() {
var g = function() {
return 1;
};
console.log(g() + h());
var h = function() {
return 2;
};
}
}
expect: {
function f() {
console.log(1 + h());
var h = function() {
return 2;
};
}
}
}
func_modified: {
options = {
reduce_vars: true,
unused: true,
}
input: {
function f(a) {
function a() { return 1; }
function b() { return 2; }
function c() { return 3; }
b.inject = [];
c = function() { return 4; };
return a() + b() + c();
}
}
expect: {
function f(a) {
function b() { return 2; }
function c() { return 3; }
b.inject = [];
c = function() { return 4; };
return 1 + 2 + c();
}
}
}

2
test/mocha/cli.js
View File

@@ -82,7 +82,7 @@ describe("bin/uglifyjs", function () {
});
});
it("Should work with --keep-fnames (mangle & compress)", function (done) {
var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c';
var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c unused=false';
exec(command, function (err, stdout) {
if (err) throw err;

12
test/mocha/glob.js
View File

@@ -3,17 +3,13 @@ var assert = require("assert");
describe("minify() with input file globs", function() {
it("minify() with one input file glob string.", function() {
var result = Uglify.minify("test/input/issue-1242/foo.*", {
compress: { collapse_vars: true }
});
var result = Uglify.minify("test/input/issue-1242/foo.*");
assert.strictEqual(result.code, 'function foo(o){print("Foo:",2*o)}var print=console.log.bind(console);');
});
it("minify() with an array of one input file glob.", function() {
var result = Uglify.minify([
"test/input/issue-1242/b*.es5",
], {
compress: { collapse_vars: true }
});
]);
assert.strictEqual(result.code, 'function bar(n){return 3*n}function baz(n){return n/2}');
});
it("minify() with an array of multiple input file globs.", function() {
@@ -21,8 +17,8 @@ describe("minify() with input file globs", function() {
"test/input/issue-1242/???.es5",
"test/input/issue-1242/*.js",
], {
compress: { collapse_vars: true }
compress: { toplevel: true }
});
assert.strictEqual(result.code, 'function bar(n){return 3*n}function baz(n){return n/2}function foo(n){print("Foo:",2*n)}var print=console.log.bind(console);print("qux",bar(3),baz(12)),foo(11);');
assert.strictEqual(result.code, 'var print=console.log.bind(console);print("qux",function(n){return 3*n}(3),function(n){return n/2}(12)),function(n){print("Foo:",2*n)}(11);');
});
});