JoBoEVD/UglifyJS
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fix corner cases in aliasing of global variables (#4039)

Browse Source 
fixes #4038
This commit is contained in:
Alex Lam S.L
2020-08-06 09:39:50 +01:00
committed by GitHub
parent 30ef20a208
commit 9b05494ebc
4 changed files with 115 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
lib/compress.js
View File

@@ -167,7 +167,7 @@ merge(Compressor.prototype, {
if (def.global) for (var i = 0; i < def.orig.length; i++)
if (!this.toplevel[def.orig[i] instanceof AST_SymbolDefun ? "funcs" : "vars"])
return true;
return false;
return def.undeclared;
},
compress: function(node) {
node = node.resolve_defines(this);
@@ -1386,6 +1386,7 @@ merge(Compressor.prototype, {
var scan_lhs = lhs && !side_effects && !is_lhs_read_only(lhs, compressor);
var scan_rhs = foldable(candidate);
if (!scan_lhs && !scan_rhs) continue;
var read_toplevel = false;
var modify_toplevel = false;
// Locate symbols which may execute code outside of scanning range
var lvalues = get_lvalues(candidate);
@@ -1548,8 +1549,10 @@ merge(Compressor.prototype, {
return lvalues.has(node.name.name) || side_effects && may_modify(node.name);
}
var sym = is_lhs(node.left, node);
if (sym && lvalues.has(sym.name)) return true;
if (sym instanceof AST_PropAccess) return true;
if (!sym) return false;
return lvalues.has(sym.name)
|| sym instanceof AST_PropAccess
|| read_toplevel && compressor.exposed(sym.definition());
}
function extract_args() {
@@ -1936,26 +1939,43 @@ merge(Compressor.prototype, {
};
}
function may_be_global(node) {
if (node instanceof AST_SymbolRef) {
node = node.fixed_value();
if (!node) return true;
}
if (node instanceof AST_Assign) return node.operator == "=" && may_be_global(node.right);
return node instanceof AST_PropAccess || node instanceof AST_This;
}
function get_lvalues(expr) {
var lvalues = new Dictionary();
if (candidate instanceof AST_VarDef) lvalues.add(candidate.name.name, lhs);
var scan_iife = scope instanceof AST_Toplevel;
if (expr instanceof AST_VarDef) lvalues.add(expr.name.name, lhs);
var scan_toplevel = scope instanceof AST_Toplevel;
var tw = new TreeWalker(function(node) {
if (scan_iife && node.TYPE == "Call") {
var exp = node.expression;
if (exp instanceof AST_PropAccess) return;
if (exp instanceof AST_Function && !exp.contains_this()) return;
modify_toplevel = true;
scan_iife = false;
return;
}
var value;
if (node instanceof AST_SymbolRef) {
value = node.fixed_value() || node;
} else if (node instanceof AST_This) {
value = node;
}
if (value) lvalues.add(node.name, is_modified(compressor, tw, node, value, 0));
if (value) {
lvalues.add(node.name, is_modified(compressor, tw, node, value, 0));
} else if (scan_toplevel) {
if (node.TYPE == "Call") {
if (modify_toplevel) return;
var exp = node.expression;
if (exp instanceof AST_PropAccess) return;
if (exp instanceof AST_Function && !exp.contains_this()) return;
modify_toplevel = true;
} else if (node instanceof AST_PropAccess && may_be_global(node.expression)) {
if (node === lhs && !(expr instanceof AST_Unary)) {
modify_toplevel = true;
} else {
read_toplevel = true;
}
}
}
});
expr.walk(tw);
return lvalues;