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| author | Alex Lam S.L <alexlamsl@gmail.com> | 2021-05-11 03:30:20 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-05-11 10:30:20 +0800 |
| commit | b1cfa7113129e15a621aa5fd5750bca3b4a7250c (patch) | |
| tree | bb14f6024b8513e7761aad38f847be69cdcb5875 | |
| parent | 7b8570f16c90905976cc8eb0e377800e7404ef4d (diff) | |
| download | tracifyjs-b1cfa7113129e15a621aa5fd5750bca3b4a7250c.tar.gz tracifyjs-b1cfa7113129e15a621aa5fd5750bca3b4a7250c.zip | |
enhance `unused` (#4922)
| -rw-r--r-- | lib/compress.js | 28 | ||||
| -rw-r--r-- | test/compress/drop-unused.js | 2 |
2 files changed, 16 insertions, 14 deletions
diff --git a/lib/compress.js b/lib/compress.js index 3e8d8946..7d6dd704 100644 --- a/lib/compress.js +++ b/lib/compress.js @@ -6057,7 +6057,7 @@ merge(Compressor.prototype, { if (!side_effects) { initializations.add(def.id, value); } else if (shared) { - verify_safe_usage(def, true, value_modified[def.id]); + verify_safe_usage(def, name, value_modified[def.id]); } assignments.add(def.id, defn); } @@ -6200,19 +6200,13 @@ merge(Compressor.prototype, { if (drop_vars) { var props = [], sym = assign_as_unused(node, props); if (sym) { - var def = sym.definition(); - var in_use = def.id in in_use_ids; var value; - if (node instanceof AST_Assign) { - if (!in_use || node.left === sym && indexOf_assign(def, node) < 0) { + if (can_drop_lhs(sym, node)) { + if (node instanceof AST_Assign) { value = get_rhs(node); - if (node.write_only === true) { - value = value.drop_side_effect_free(compressor) - || make_node(AST_Number, node, { value: 0 }); - } + if (node.write_only === true) value = value.drop_side_effect_free(compressor); } - } else if (!in_use || node.expression === sym && indexOf_assign(def, node) < 0) { - value = make_node(AST_Number, node, { value: 0 }); + if (!value) value = make_node(AST_Number, node, { value: 0 }); } if (value) { if (props.assign) { @@ -6705,7 +6699,7 @@ merge(Compressor.prototype, { function verify_safe_usage(def, read, modified) { if (def.id in in_use_ids) return; if (read && modified) { - in_use_ids[def.id] = true; + in_use_ids[def.id] = read; in_use.push(def); } else { value_read[def.id] = read; @@ -6713,6 +6707,14 @@ merge(Compressor.prototype, { } } + function can_drop_lhs(sym, node) { + var def = sym.definition(); + var in_use = in_use_ids[def.id]; + if (!in_use) return true; + if (node[node instanceof AST_Assign ? "left" : "expression"] !== sym) return false; + return in_use === sym && def.references.length - def.replaced == 1 || indexOf_assign(def, node) < 0; + } + function get_rhs(assign) { var rhs = assign.right; if (!assign.write_only) return rhs; @@ -6775,7 +6777,7 @@ merge(Compressor.prototype, { } if (node.left === sym) { if (!node.write_only || shared) { - verify_safe_usage(node_def, true, value_modified[node_def.id]); + verify_safe_usage(node_def, sym, value_modified[node_def.id]); } } else { var fixed = sym.fixed_value(); diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js index 709ed922..5ca29b04 100644 --- a/test/compress/drop-unused.js +++ b/test/compress/drop-unused.js @@ -3436,7 +3436,7 @@ issue_4912_2: { console.log(function() { var g, f = function() {}; f.p = {}; - (g = f.p.q = function() {}).r = "PASS"; + (f.p.q = function() {}).r = "PASS"; return f; }().p.q.r); } |