diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/compress.js | 109 |
1 files changed, 35 insertions, 74 deletions
diff --git a/lib/compress.js b/lib/compress.js index 004858ac..6e984ffa 100644 --- a/lib/compress.js +++ b/lib/compress.js @@ -49,7 +49,6 @@ function Compressor(options, false_by_default) { TreeTransformer.call(this, this.before, this.after); this.options = defaults(options, { booleans : !false_by_default, - cascade : !false_by_default, collapse_vars : !false_by_default, comparisons : !false_by_default, conditionals : !false_by_default, @@ -884,6 +883,8 @@ merge(Compressor.prototype, { if (!hit) { if (node === candidate) { hit = true; + stop_after = find_stop(node, 0); + if (stop_after === node) abort = true; return node; } return; @@ -963,12 +964,13 @@ merge(Compressor.prototype, { && (parent instanceof AST_Binary && lazy_op(parent.operator) || parent instanceof AST_Conditional || parent instanceof AST_If)) { - if (!(node instanceof AST_Scope)) descend(node, scanner); - abort = true; - return node; + stop_after = node; + if (node instanceof AST_Scope) abort = true; } // Skip (non-executed) functions if (node instanceof AST_Scope) return node; + }, function(node) { + if (!abort && stop_after === node) abort = true; }); var multi_replacer = new TreeTransformer(function(node) { if (abort) return node; @@ -1003,6 +1005,7 @@ merge(Compressor.prototype, { while (candidates.length > 0) { var candidate = candidates.pop(); var value_def = null; + var stop_after = null; var lhs = get_lhs(candidate); if (!lhs || is_lhs_read_only(lhs) || lhs.has_side_effects(compressor)) continue; // Locate symbols which may execute code outside of scanning range @@ -1094,19 +1097,43 @@ merge(Compressor.prototype, { if (expr instanceof AST_Assign && !expr.left.has_side_effects(compressor) || expr instanceof AST_Unary && (expr.operator == "++" || expr.operator == "--")) { candidates.push(expr); - } else if (expr instanceof AST_Sequence) { - expr.expressions.forEach(extract_candidates); + } else if (expr instanceof AST_Case) { + extract_candidates(expr.expression); + } else if (expr instanceof AST_Conditional) { + extract_candidates(expr.condition); + extract_candidates(expr.consequent); + extract_candidates(expr.alternative); } else if (expr instanceof AST_Definitions) { expr.definitions.forEach(function(var_def) { if (var_def.value) candidates.push(var_def); }); + } else if (expr instanceof AST_Exit) { + if (expr.value) extract_candidates(expr.value); + } else if (expr instanceof AST_For) { + if (expr.init) extract_candidates(expr.init); + } else if (expr instanceof AST_If) { + extract_candidates(expr.condition); + } else if (expr instanceof AST_Sequence) { + expr.expressions.forEach(extract_candidates); } else if (expr instanceof AST_SimpleStatement) { extract_candidates(expr.body); - } else if (expr instanceof AST_For && expr.init) { - extract_candidates(expr.init); + } else if (expr instanceof AST_Switch) { + extract_candidates(expr.expression); + expr.body.forEach(extract_candidates); } } + function find_stop(node, level) { + var parent = scanner.parent(level); + if (parent instanceof AST_Case) return node; + if (parent instanceof AST_Conditional) return node; + if (parent instanceof AST_Exit) return node; + if (parent instanceof AST_If) return node; + if (parent instanceof AST_Sequence) return find_stop(parent, level + 1); + if (parent instanceof AST_Switch) return node; + return null; + } + function mangleable_var(var_def) { var value = var_def.value; if (!(value instanceof AST_SymbolRef)) return; @@ -3898,7 +3925,6 @@ merge(Compressor.prototype, { filter_for_side_effects(); var end = expressions.length - 1; trim_right_for_undefined(); - if (end > 0 && compressor.option("cascade")) trim_left_for_assignment(); if (end == 0) { self = maintain_this_binding(compressor.parent(), compressor.self(), expressions[0]); if (!(self instanceof AST_Sequence)) self = self.optimize(compressor); @@ -3929,71 +3955,6 @@ merge(Compressor.prototype, { expressions.length = end + 1; } } - - function trim_left_for_assignment() { - for (var i = 0, j = 1; j <= end; j++) { - var left = expressions[i]; - var cdr = expressions[j]; - if (left instanceof AST_Assign - && !left.left.has_side_effects(compressor)) { - left = left.left; - } else if (left instanceof AST_Unary - && (left.operator == "++" || left.operator == "--")) { - left = left.expression; - } else left = null; - if (!left || is_lhs_read_only(left) || left.has_side_effects(compressor)) { - expressions[++i] = cdr; - continue; - } - var parent = null, field; - expressions[j] = cdr = cdr.clone(); - while (true) { - if (cdr.equivalent_to(left)) { - var car = expressions[i]; - if (car instanceof AST_UnaryPostfix) { - car = make_node(AST_UnaryPrefix, car, { - operator: car.operator, - expression: left - }); - } else { - car.write_only = false; - } - if (parent) { - parent[field] = car; - expressions[i] = expressions[j]; - } else { - expressions[i] = car; - } - break; - } - if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) { - if (cdr.left.is_constant()) { - if (lazy_op(cdr.operator)) { - expressions[++i] = expressions[j]; - break; - } - field = "right"; - } else { - field = "left"; - } - } else if (cdr instanceof AST_Call - && !(left instanceof AST_PropAccess && cdr.expression.equivalent_to(left)) - || cdr instanceof AST_PropAccess - || cdr instanceof AST_Unary && !unary_side_effects(cdr.operator)) { - field = "expression"; - } else if (cdr instanceof AST_Conditional) { - field = "condition"; - } else { - expressions[++i] = expressions[j]; - break; - } - parent = cdr; - cdr = cdr[field] = cdr[field].clone(); - } - } - end = i; - expressions.length = end + 1; - } }); AST_Unary.DEFMETHOD("lift_sequences", function(compressor){ |