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enhance loops & unused (#4074)

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- extend `ufuzz` generation of for-in loops
This commit is contained in:
Alex Lam S.L
2020-08-26 02:32:55 +01:00
committed by GitHub
parent 09525c7530
commit c7a3e09407
3 changed files with 67 additions and 22 deletions
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42
lib/compress.js
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@@ -4456,7 +4456,7 @@ merge(Compressor.prototype, {
if (drop_funcs && node !== self && node instanceof AST_Defun) {
var def = node.name.definition();
if (!(def.id in in_use_ids)) {
log(node.name, "Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
log(node.name, "Dropping unused function {name}");
def.eliminated++;
return in_list ? List.skip : make_node(AST_EmptyStatement, node);
}
@@ -4471,7 +4471,7 @@ merge(Compressor.prototype, {
if (!(sym.definition().id in in_use_ids)) {
sym.__unused = true;
if (trim) {
log(sym, "Dropping unused function argument {name} [{file}:{line},{col}]", template(sym));
log(sym, "Dropping unused function argument {name}");
a.pop();
}
} else {
@@ -4574,7 +4574,7 @@ merge(Compressor.prototype, {
AST_Node.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
side_effects.push(value);
} else {
log(def.name, "Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
log(def.name, "Dropping unused variable {name}");
}
sym.eliminated++;
}
@@ -4669,19 +4669,22 @@ merge(Compressor.prototype, {
return !block ? node : in_list ? List.splice(block.body) : block;
} else if (node instanceof AST_ForIn) {
if (!drop_vars || !compressor.option("loops")) return;
if (!(node.init instanceof AST_Definitions)) return;
var sym = node.init.definitions[0].name;
if (sym.definition().id in in_use_ids) return;
if (!is_empty(node.body)) return;
log(sym, "Dropping unused loop variable {name} [{file}:{line},{col}]", template(sym));
var value = node.object.drop_side_effect_free(compressor);
if (value) {
AST_Node.warn("Side effects in object of for-in loop [{file}:{line},{col}]", template(sym));
return make_node(AST_SimpleStatement, node, {
body: value
});
var sym = node.init;
if (sym instanceof AST_Definitions) {
sym = sym.definitions[0].name;
} else while (sym instanceof AST_PropAccess) {
sym = sym.expression.tail_node();
}
return in_list ? List.skip : make_node(AST_EmptyStatement, node);
var def = sym.definition();
if (!def || def.id in in_use_ids) return;
log(sym, "Dropping unused loop variable {name}");
var value = node.object.drop_side_effect_free(compressor);
if (!value) return in_list ? List.skip : make_node(AST_EmptyStatement, node);
AST_Node.warn("Side effects in object of for-in loop [{file}:{line},{col}]", value.start);
return make_node(AST_SimpleStatement, node, {
body: value
});
} else if (node instanceof AST_Sequence) {
if (node.expressions.length == 1) return node.expressions[0];
}
@@ -4701,8 +4704,8 @@ merge(Compressor.prototype, {
drop_unused_call_args(call, compressor, fns_with_marked_args);
});
function log(sym, text, props) {
AST_Node[sym.definition().references.length > 0 ? "info" : "warn"](text, props);
function log(sym, text) {
AST_Node[sym.definition().references.length > 0 ? "info" : "warn"](text + " [{file}:{line},{col}]", template(sym));
}
function template(sym) {
@@ -4790,6 +4793,13 @@ merge(Compressor.prototype, {
if (track_assigns(node_def, sym) && is_lhs(sym, node) !== sym) add_assigns(node_def, sym);
return true;
}
if (node instanceof AST_ForIn) {
if (!compressor.option("loops")) return;
if (!is_empty(node.body)) return;
if (node.init.has_side_effects(compressor)) return;
node.object.walk(tw);
return true;
}
if (node instanceof AST_SymbolRef) {
node_def = node.definition();
if (!(node_def.id in in_use_ids)) {