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625 lines
22 KiB
625 lines
22 KiB
/***********************************************************************
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A JavaScript tokenizer / parser / beautifier / compressor.
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https://github.com/mishoo/UglifyJS2
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-------------------------------- (C) ---------------------------------
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Author: Mihai Bazon
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<mihai.bazon@gmail.com>
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http://mihai.bazon.net/blog
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Distributed under the BSD license:
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Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the following
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disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials
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provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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SUCH DAMAGE.
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***********************************************************************/
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import {
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AST_Array,
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AST_Assign,
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AST_Block,
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AST_Call,
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AST_Catch,
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AST_Class,
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AST_ClassExpression,
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AST_DefaultAssign,
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AST_DefClass,
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AST_Defun,
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AST_Destructuring,
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AST_EmptyStatement,
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AST_Expansion,
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AST_Export,
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AST_Function,
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AST_IterationStatement,
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AST_Lambda,
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AST_Node,
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AST_Number,
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AST_Object,
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AST_ObjectKeyVal,
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AST_PropAccess,
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AST_Return,
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AST_Scope,
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AST_SimpleStatement,
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AST_Statement,
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AST_SymbolDefun,
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AST_SymbolFunarg,
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AST_SymbolLambda,
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AST_SymbolRef,
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AST_SymbolVar,
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AST_This,
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AST_Toplevel,
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AST_UnaryPrefix,
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AST_Undefined,
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AST_Var,
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AST_VarDef,
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walk,
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_INLINE,
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_NOINLINE,
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_PURE
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} from "../ast.js";
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import { make_node, has_annotation } from "../utils/index.js";
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import "../size.js";
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import "./evaluate.js";
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import "./drop-side-effect-free.js";
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import "./reduce-vars.js";
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import { is_lhs } from "./inference.js";
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import {
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SQUEEZED,
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INLINED,
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UNUSED,
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has_flag,
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set_flag,
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} from "./compressor-flags.js";
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import {
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make_sequence,
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best_of,
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make_node_from_constant,
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identifier_atom,
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is_empty,
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is_func_expr,
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is_iife_call,
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is_reachable,
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is_recursive_ref,
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retain_top_func,
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} from "./common.js";
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function within_array_or_object_literal(compressor) {
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var node, level = 0;
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while (node = compressor.parent(level++)) {
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if (node instanceof AST_Statement) return false;
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if (node instanceof AST_Array
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|| node instanceof AST_ObjectKeyVal
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|| node instanceof AST_Object) {
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return true;
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}
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}
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return false;
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}
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function scope_encloses_variables_in_this_scope(scope, pulled_scope) {
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for (const enclosed of pulled_scope.enclosed) {
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if (pulled_scope.variables.has(enclosed.name)) {
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continue;
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}
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const looked_up = scope.find_variable(enclosed.name);
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if (looked_up) {
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if (looked_up === enclosed) continue;
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return true;
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}
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}
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return false;
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}
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export function inline_into_symbolref(self, compressor) {
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const parent = compressor.parent();
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if (compressor.option("reduce_vars") && is_lhs(self, parent) !== self) {
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const def = self.definition();
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const nearest_scope = compressor.find_scope();
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if (compressor.top_retain && def.global && compressor.top_retain(def)) {
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def.fixed = false;
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def.single_use = false;
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return self;
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}
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let fixed = self.fixed_value();
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let single_use = def.single_use
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&& !(parent instanceof AST_Call
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&& (parent.is_callee_pure(compressor))
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|| has_annotation(parent, _NOINLINE))
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&& !(parent instanceof AST_Export
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&& fixed instanceof AST_Lambda
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&& fixed.name);
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if (single_use && fixed instanceof AST_Node) {
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single_use =
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!fixed.has_side_effects(compressor)
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&& !fixed.may_throw(compressor);
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}
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if (single_use && (fixed instanceof AST_Lambda || fixed instanceof AST_Class)) {
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if (retain_top_func(fixed, compressor)) {
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single_use = false;
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} else if (def.scope !== self.scope
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&& (def.escaped == 1
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|| has_flag(fixed, INLINED)
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|| within_array_or_object_literal(compressor)
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|| !compressor.option("reduce_funcs"))) {
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single_use = false;
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} else if (is_recursive_ref(compressor, def)) {
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single_use = false;
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} else if (def.scope !== self.scope || def.orig[0] instanceof AST_SymbolFunarg) {
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single_use = fixed.is_constant_expression(self.scope);
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if (single_use == "f") {
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var scope = self.scope;
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do {
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if (scope instanceof AST_Defun || is_func_expr(scope)) {
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set_flag(scope, INLINED);
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}
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} while (scope = scope.parent_scope);
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}
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}
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}
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if (single_use && (fixed instanceof AST_Lambda || fixed instanceof AST_Class)) {
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single_use =
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def.scope === self.scope
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&& !scope_encloses_variables_in_this_scope(nearest_scope, fixed)
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|| parent instanceof AST_Call
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&& parent.expression === self
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&& !scope_encloses_variables_in_this_scope(nearest_scope, fixed)
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&& !(fixed.name && fixed.name.definition().recursive_refs > 0);
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}
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if (single_use && fixed) {
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if (fixed instanceof AST_DefClass) {
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set_flag(fixed, SQUEEZED);
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fixed = make_node(AST_ClassExpression, fixed, fixed);
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}
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if (fixed instanceof AST_Defun) {
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set_flag(fixed, SQUEEZED);
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fixed = make_node(AST_Function, fixed, fixed);
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}
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if (def.recursive_refs > 0 && fixed.name instanceof AST_SymbolDefun) {
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const defun_def = fixed.name.definition();
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let lambda_def = fixed.variables.get(fixed.name.name);
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let name = lambda_def && lambda_def.orig[0];
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if (!(name instanceof AST_SymbolLambda)) {
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name = make_node(AST_SymbolLambda, fixed.name, fixed.name);
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name.scope = fixed;
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fixed.name = name;
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lambda_def = fixed.def_function(name);
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}
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walk(fixed, node => {
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if (node instanceof AST_SymbolRef && node.definition() === defun_def) {
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node.thedef = lambda_def;
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lambda_def.references.push(node);
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}
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});
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}
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if (
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(fixed instanceof AST_Lambda || fixed instanceof AST_Class)
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&& fixed.parent_scope !== nearest_scope
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) {
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fixed = fixed.clone(true, compressor.get_toplevel());
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nearest_scope.add_child_scope(fixed);
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}
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return fixed.optimize(compressor);
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}
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// multiple uses
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if (fixed) {
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let replace;
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if (fixed instanceof AST_This) {
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if (!(def.orig[0] instanceof AST_SymbolFunarg)
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&& def.references.every((ref) =>
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def.scope === ref.scope
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)) {
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replace = fixed;
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}
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} else {
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var ev = fixed.evaluate(compressor);
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if (
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ev !== fixed
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&& (compressor.option("unsafe_regexp") || !(ev instanceof RegExp))
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) {
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replace = make_node_from_constant(ev, fixed);
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}
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}
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if (replace) {
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const name_length = self.size(compressor);
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const replace_size = replace.size(compressor);
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let overhead = 0;
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if (compressor.option("unused") && !compressor.exposed(def)) {
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overhead =
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(name_length + 2 + replace_size) /
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(def.references.length - def.assignments);
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}
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if (replace_size <= name_length + overhead) {
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return replace;
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}
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}
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}
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}
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return self;
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}
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export function inline_into_call(self, fn, compressor) {
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var exp = self.expression;
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var simple_args = self.args.every((arg) => !(arg instanceof AST_Expansion));
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if (compressor.option("reduce_vars")
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&& fn instanceof AST_SymbolRef
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&& !has_annotation(self, _NOINLINE)
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) {
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const fixed = fn.fixed_value();
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if (!retain_top_func(fixed, compressor)) {
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fn = fixed;
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}
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}
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var is_func = fn instanceof AST_Lambda;
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var stat = is_func && fn.body[0];
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var is_regular_func = is_func && !fn.is_generator && !fn.async;
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var can_inline = is_regular_func && compressor.option("inline") && !self.is_callee_pure(compressor);
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if (can_inline && stat instanceof AST_Return) {
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let returned = stat.value;
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if (!returned || returned.is_constant_expression()) {
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if (returned) {
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returned = returned.clone(true);
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} else {
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returned = make_node(AST_Undefined, self);
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}
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const args = self.args.concat(returned);
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return make_sequence(self, args).optimize(compressor);
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}
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// optimize identity function
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if (
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fn.argnames.length === 1
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&& (fn.argnames[0] instanceof AST_SymbolFunarg)
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&& self.args.length < 2
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&& !(self.args[0] instanceof AST_Expansion)
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&& returned instanceof AST_SymbolRef
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&& returned.name === fn.argnames[0].name
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) {
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const replacement =
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(self.args[0] || make_node(AST_Undefined)).optimize(compressor);
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let parent;
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if (
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replacement instanceof AST_PropAccess
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&& (parent = compressor.parent()) instanceof AST_Call
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&& parent.expression === self
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) {
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// identity function was being used to remove `this`, like in
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//
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// id(bag.no_this)(...)
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//
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// Replace with a larger but more effish (0, bag.no_this) wrapper.
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return make_sequence(self, [
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make_node(AST_Number, self, { value: 0 }),
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replacement
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]);
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}
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// replace call with first argument or undefined if none passed
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return replacement;
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}
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}
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if (can_inline) {
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var scope, in_loop, level = -1;
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let def;
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let returned_value;
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let nearest_scope;
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if (simple_args
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&& !fn.uses_arguments
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&& !(compressor.parent() instanceof AST_Class)
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&& !(fn.name && fn instanceof AST_Function)
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&& (returned_value = can_flatten_body(stat))
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&& (exp === fn
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|| has_annotation(self, _INLINE)
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|| compressor.option("unused")
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&& (def = exp.definition()).references.length == 1
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&& !is_recursive_ref(compressor, def)
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&& fn.is_constant_expression(exp.scope))
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&& !has_annotation(self, _PURE | _NOINLINE)
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&& !fn.contains_this()
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&& can_inject_symbols()
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&& (nearest_scope = compressor.find_scope())
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&& !scope_encloses_variables_in_this_scope(nearest_scope, fn)
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&& !(function in_default_assign() {
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// Due to the fact function parameters have their own scope
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// which can't use `var something` in the function body within,
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// we simply don't inline into DefaultAssign.
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let i = 0;
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let p;
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while ((p = compressor.parent(i++))) {
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if (p instanceof AST_DefaultAssign) return true;
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if (p instanceof AST_Block) break;
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}
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return false;
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})()
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&& !(scope instanceof AST_Class)
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) {
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set_flag(fn, SQUEEZED);
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nearest_scope.add_child_scope(fn);
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return make_sequence(self, flatten_fn(returned_value)).optimize(compressor);
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}
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}
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if (can_inline && has_annotation(self, _INLINE)) {
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set_flag(fn, SQUEEZED);
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fn = make_node(fn.CTOR === AST_Defun ? AST_Function : fn.CTOR, fn, fn);
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fn = fn.clone(true);
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fn.figure_out_scope({}, {
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parent_scope: compressor.find_scope(),
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toplevel: compressor.get_toplevel()
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});
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return make_node(AST_Call, self, {
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expression: fn,
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args: self.args,
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}).optimize(compressor);
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}
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const can_drop_this_call = is_regular_func && compressor.option("side_effects") && fn.body.every(is_empty);
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if (can_drop_this_call) {
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var args = self.args.concat(make_node(AST_Undefined, self));
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return make_sequence(self, args).optimize(compressor);
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}
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if (compressor.option("negate_iife")
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&& compressor.parent() instanceof AST_SimpleStatement
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&& is_iife_call(self)) {
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return self.negate(compressor, true);
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}
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var ev = self.evaluate(compressor);
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if (ev !== self) {
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ev = make_node_from_constant(ev, self).optimize(compressor);
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return best_of(compressor, ev, self);
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}
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return self;
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function return_value(stat) {
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if (!stat) return make_node(AST_Undefined, self);
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if (stat instanceof AST_Return) {
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if (!stat.value) return make_node(AST_Undefined, self);
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return stat.value.clone(true);
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}
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if (stat instanceof AST_SimpleStatement) {
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return make_node(AST_UnaryPrefix, stat, {
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operator: "void",
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expression: stat.body.clone(true)
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});
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}
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}
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function can_flatten_body(stat) {
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var body = fn.body;
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var len = body.length;
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if (compressor.option("inline") < 3) {
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return len == 1 && return_value(stat);
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}
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stat = null;
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for (var i = 0; i < len; i++) {
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var line = body[i];
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if (line instanceof AST_Var) {
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if (stat && !line.definitions.every((var_def) =>
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!var_def.value
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)) {
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return false;
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}
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} else if (stat) {
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return false;
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} else if (!(line instanceof AST_EmptyStatement)) {
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stat = line;
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}
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}
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return return_value(stat);
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}
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|
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function can_inject_args(block_scoped, safe_to_inject) {
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for (var i = 0, len = fn.argnames.length; i < len; i++) {
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var arg = fn.argnames[i];
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if (arg instanceof AST_DefaultAssign) {
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if (has_flag(arg.left, UNUSED)) continue;
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return false;
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}
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if (arg instanceof AST_Destructuring) return false;
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if (arg instanceof AST_Expansion) {
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if (has_flag(arg.expression, UNUSED)) continue;
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return false;
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}
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if (has_flag(arg, UNUSED)) continue;
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if (!safe_to_inject
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|| block_scoped.has(arg.name)
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|| identifier_atom.has(arg.name)
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|| scope.conflicting_def(arg.name)) {
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return false;
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}
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if (in_loop) in_loop.push(arg.definition());
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}
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return true;
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}
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function can_inject_vars(block_scoped, safe_to_inject) {
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var len = fn.body.length;
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for (var i = 0; i < len; i++) {
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var stat = fn.body[i];
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if (!(stat instanceof AST_Var)) continue;
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if (!safe_to_inject) return false;
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for (var j = stat.definitions.length; --j >= 0;) {
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var name = stat.definitions[j].name;
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if (name instanceof AST_Destructuring
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|| block_scoped.has(name.name)
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|| identifier_atom.has(name.name)
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|| scope.conflicting_def(name.name)) {
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return false;
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}
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if (in_loop) in_loop.push(name.definition());
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}
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}
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return true;
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}
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function can_inject_symbols() {
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var block_scoped = new Set();
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do {
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scope = compressor.parent(++level);
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if (scope.is_block_scope() && scope.block_scope) {
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// TODO this is sometimes undefined during compression.
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// But it should always have a value!
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scope.block_scope.variables.forEach(function (variable) {
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block_scoped.add(variable.name);
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});
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}
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if (scope instanceof AST_Catch) {
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// TODO can we delete? AST_Catch is a block scope.
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if (scope.argname) {
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block_scoped.add(scope.argname.name);
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}
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} else if (scope instanceof AST_IterationStatement) {
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in_loop = [];
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} else if (scope instanceof AST_SymbolRef) {
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if (scope.fixed_value() instanceof AST_Scope) return false;
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}
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} while (!(scope instanceof AST_Scope));
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|
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var safe_to_inject = !(scope instanceof AST_Toplevel) || compressor.toplevel.vars;
|
|
var inline = compressor.option("inline");
|
|
if (!can_inject_vars(block_scoped, inline >= 3 && safe_to_inject)) return false;
|
|
if (!can_inject_args(block_scoped, inline >= 2 && safe_to_inject)) return false;
|
|
return !in_loop || in_loop.length == 0 || !is_reachable(fn, in_loop);
|
|
}
|
|
|
|
function append_var(decls, expressions, name, value) {
|
|
var def = name.definition();
|
|
|
|
// Name already exists, only when a function argument had the same name
|
|
const already_appended = scope.variables.has(name.name);
|
|
if (!already_appended) {
|
|
scope.variables.set(name.name, def);
|
|
scope.enclosed.push(def);
|
|
decls.push(make_node(AST_VarDef, name, {
|
|
name: name,
|
|
value: null
|
|
}));
|
|
}
|
|
|
|
var sym = make_node(AST_SymbolRef, name, name);
|
|
def.references.push(sym);
|
|
if (value) expressions.push(make_node(AST_Assign, self, {
|
|
operator: "=",
|
|
logical: false,
|
|
left: sym,
|
|
right: value.clone()
|
|
}));
|
|
}
|
|
|
|
function flatten_args(decls, expressions) {
|
|
var len = fn.argnames.length;
|
|
for (var i = self.args.length; --i >= len;) {
|
|
expressions.push(self.args[i]);
|
|
}
|
|
for (i = len; --i >= 0;) {
|
|
var name = fn.argnames[i];
|
|
var value = self.args[i];
|
|
if (has_flag(name, UNUSED) || !name.name || scope.conflicting_def(name.name)) {
|
|
if (value) expressions.push(value);
|
|
} else {
|
|
var symbol = make_node(AST_SymbolVar, name, name);
|
|
name.definition().orig.push(symbol);
|
|
if (!value && in_loop) value = make_node(AST_Undefined, self);
|
|
append_var(decls, expressions, symbol, value);
|
|
}
|
|
}
|
|
decls.reverse();
|
|
expressions.reverse();
|
|
}
|
|
|
|
function flatten_vars(decls, expressions) {
|
|
var pos = expressions.length;
|
|
for (var i = 0, lines = fn.body.length; i < lines; i++) {
|
|
var stat = fn.body[i];
|
|
if (!(stat instanceof AST_Var)) continue;
|
|
for (var j = 0, defs = stat.definitions.length; j < defs; j++) {
|
|
var var_def = stat.definitions[j];
|
|
var name = var_def.name;
|
|
append_var(decls, expressions, name, var_def.value);
|
|
if (in_loop && fn.argnames.every((argname) =>
|
|
argname.name != name.name
|
|
)) {
|
|
var def = fn.variables.get(name.name);
|
|
var sym = make_node(AST_SymbolRef, name, name);
|
|
def.references.push(sym);
|
|
expressions.splice(pos++, 0, make_node(AST_Assign, var_def, {
|
|
operator: "=",
|
|
logical: false,
|
|
left: sym,
|
|
right: make_node(AST_Undefined, name)
|
|
}));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
function flatten_fn(returned_value) {
|
|
var decls = [];
|
|
var expressions = [];
|
|
flatten_args(decls, expressions);
|
|
flatten_vars(decls, expressions);
|
|
expressions.push(returned_value);
|
|
|
|
if (decls.length) {
|
|
const i = scope.body.indexOf(compressor.parent(level - 1)) + 1;
|
|
scope.body.splice(i, 0, make_node(AST_Var, fn, {
|
|
definitions: decls
|
|
}));
|
|
}
|
|
|
|
return expressions.map(exp => exp.clone(true));
|
|
}
|
|
}
|