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handle overlapped variable definitions (#1691)

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Process variable definitions with or without assigned values against:
- `arguments`
- named function arguments
- multiple definitions within same scope

Essentially demote variable declarations with no value assignments.

Also fixed invalid use of `AST_VarDef` over `arguments` - should use a member of `AST_SymbolDeclaration` instead.
This commit is contained in:
Alex Lam S.L
2017-03-27 01:30:21 +08:00
committed by GitHub
parent 861a79ac9f
commit 57ce5bd9e0
3 changed files with 314 additions and 24 deletions
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17
lib/compress.js
View File

@@ -260,7 +260,7 @@ merge(Compressor.prototype, {
if (node instanceof AST_SymbolRef) {
var d = node.definition();
d.references.push(node);
if (!d.fixed || !is_safe(d)
if (d.fixed === undefined || !is_safe(d)
|| is_modified(node, 0, d.fixed instanceof AST_Lambda)) {
d.fixed = false;
}
@@ -270,10 +270,10 @@ merge(Compressor.prototype, {
}
if (node instanceof AST_VarDef) {
var d = node.name.definition();
if (d.fixed === undefined) {
d.fixed = node.value || make_node(AST_Undefined, node);
if (d.fixed == null) {
d.fixed = node.value;
mark_as_safe(d);
} else {
} else if (node.value) {
d.fixed = false;
}
}
@@ -357,7 +357,14 @@ merge(Compressor.prototype, {
function is_safe(def) {
for (var i = safe_ids.length, id = def.id; --i >= 0;) {
if (safe_ids[i][id]) return true;
if (safe_ids[i][id]) {
if (def.fixed == null) {
var orig = def.orig[0];
if (orig instanceof AST_SymbolFunarg || orig.name == "arguments") return false;
def.fixed = make_node(AST_Undefined, orig);
}
return true;
}
}
}

32
lib/scope.js
View File

@@ -100,15 +100,14 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
if (node instanceof AST_Catch) {
var save_scope = scope;
scope = new AST_Scope(node);
scope.init_scope_vars();
scope.parent_scope = save_scope;
scope.init_scope_vars(save_scope);
descend();
scope = save_scope;
return true;
}
if (node instanceof AST_Scope) {
node.init_scope_vars();
var save_scope = node.parent_scope = scope;
node.init_scope_vars(scope);
var save_scope = scope;
var save_defun = defun;
var save_labels = labels;
defun = scope = node;
@@ -243,23 +242,24 @@ AST_Toplevel.DEFMETHOD("def_global", function(node){
}
});
AST_Scope.DEFMETHOD("init_scope_vars", function(){
this.variables = new Dictionary(); // map name to AST_SymbolVar (variables defined in this scope; includes functions)
this.functions = new Dictionary(); // map name to AST_SymbolDefun (functions defined in this scope)
this.uses_with = false; // will be set to true if this or some nested scope uses the `with` statement
this.uses_eval = false; // will be set to true if this or nested scope uses the global `eval`
this.parent_scope = null; // the parent scope
this.enclosed = []; // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
this.cname = -1; // the current index for mangling functions/variables
AST_Scope.DEFMETHOD("init_scope_vars", function(parent_scope){
this.variables = new Dictionary(); // map name to AST_SymbolVar (variables defined in this scope; includes functions)
this.functions = new Dictionary(); // map name to AST_SymbolDefun (functions defined in this scope)
this.uses_with = false; // will be set to true if this or some nested scope uses the `with` statement
this.uses_eval = false; // will be set to true if this or nested scope uses the global `eval`
this.parent_scope = parent_scope; // the parent scope
this.enclosed = []; // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
this.cname = -1; // the current index for mangling functions/variables
});
AST_Lambda.DEFMETHOD("init_scope_vars", function(){
AST_Scope.prototype.init_scope_vars.apply(this, arguments);
this.uses_arguments = false;
var symbol = new AST_VarDef({ name: "arguments", start: this.start, end: this.end });
var def = new SymbolDef(this, this.variables.size(), symbol);
this.variables.set(symbol.name, def);
this.def_variable(new AST_SymbolVar({
name: "arguments",
start: this.start,
end: this.end
}));
});
AST_SymbolRef.DEFMETHOD("reference", function(options) {