[Pkg-javascript-commits] [uglifyjs] 467/491: allow `collapse_vars` across conditional branches (#2867)
Jonas Smedegaard
dr at jones.dk
Wed Feb 14 19:52:05 UTC 2018
This is an automated email from the git hooks/post-receive script.
js pushed a commit to annotated tag debian/3.3.10-1
in repository uglifyjs.
commit e6a2e9e4d08b73c327e95bcd4da923f9404788d0
Author: Alex Lam S.L <alexlamsl at gmail.com>
Date: Sat Feb 3 02:44:40 2018 +0800
allow `collapse_vars` across conditional branches (#2867)
---
lib/compress.js | 117 +++++++++++++++++++++++------------
test/compress/collapse_vars.js | 134 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 213 insertions(+), 38 deletions(-)
diff --git a/lib/compress.js b/lib/compress.js
index 77636cb..6f9d64f 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -952,32 +952,11 @@ merge(Compressor.prototype, {
var stat_index = statements.length;
var scanner = new TreeTransformer(function(node, descend) {
if (abort) return node;
- // Scan case expressions first in a switch statement
- if (node instanceof AST_Switch) {
- if (!hit) {
- if (node !== hit_stack[hit_index]) return node;
- hit_index++;
- }
- node.expression = node.expression.transform(scanner);
- for (var i = 0, len = node.body.length; !abort && i < len; i++) {
- var branch = node.body[i];
- if (branch instanceof AST_Case) {
- if (!hit) {
- if (branch !== hit_stack[hit_index]) continue;
- hit_index++;
- }
- branch.expression = branch.expression.transform(scanner);
- if (side_effects || !replace_all) break;
- }
- }
- abort = true;
- return node;
- }
// Skip nodes before `candidate` as quickly as possible
if (!hit) {
if (node !== hit_stack[hit_index]) return node;
hit_index++;
- if (hit_index < hit_stack.length) return;
+ if (hit_index < hit_stack.length) return handle_custom_scan_order(node);
hit = true;
stop_after = find_stop(node, 0);
if (stop_after === node) abort = true;
@@ -997,10 +976,21 @@ merge(Compressor.prototype, {
abort = true;
return node;
}
+ // Stop only if candidate is found within conditional branches
+ if (!stop_if_hit && (side_effects || !replace_all)
+ && (parent instanceof AST_Binary && lazy_op(parent.operator) && parent.left !== node
+ || parent instanceof AST_Conditional && parent.condition !== node
+ || parent instanceof AST_If && parent.condition !== node)) {
+ stop_if_hit = parent;
+ }
// Replace variable with assignment when found
if (can_replace
&& !(node instanceof AST_SymbolDeclaration)
&& lhs.equivalent_to(node)) {
+ if (stop_if_hit) {
+ abort = true;
+ return node;
+ }
if (is_lhs(node, parent)) {
if (value_def) replaced++;
return node;
@@ -1056,18 +1046,15 @@ merge(Compressor.prototype, {
|| (sym = is_lhs(node.left, node))
&& (sym instanceof AST_PropAccess || sym.name in lvalues)
|| may_throw
- && (in_try ? node.has_side_effects(compressor) : side_effects_external(node))
- || (side_effects || !replace_all)
- && (parent instanceof AST_Binary && lazy_op(parent.operator)
- || parent instanceof AST_Conditional
- || parent instanceof AST_If)) {
+ && (in_try ? node.has_side_effects(compressor) : side_effects_external(node))) {
stop_after = node;
if (node instanceof AST_Scope) abort = true;
}
- // Skip (non-executed) functions
- if (node instanceof AST_Scope) return node;
+ return handle_custom_scan_order(node);
}, function(node) {
- if (!abort && stop_after === node) abort = true;
+ if (abort) return;
+ if (stop_after === node) abort = true;
+ if (stop_if_hit === node) stop_if_hit = null;
});
var multi_replacer = new TreeTransformer(function(node) {
if (abort) return node;
@@ -1106,6 +1093,7 @@ merge(Compressor.prototype, {
var candidate = hit_stack[hit_stack.length - 1];
var value_def = null;
var stop_after = null;
+ var stop_if_hit = 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
@@ -1149,6 +1137,28 @@ merge(Compressor.prototype, {
}
}
+ function handle_custom_scan_order(node) {
+ // Skip (non-executed) functions
+ if (node instanceof AST_Scope) return node;
+ // Scan case expressions first in a switch statement
+ if (node instanceof AST_Switch) {
+ node.expression = node.expression.transform(scanner);
+ for (var i = 0, len = node.body.length; !abort && i < len; i++) {
+ var branch = node.body[i];
+ if (branch instanceof AST_Case) {
+ if (!hit) {
+ if (branch !== hit_stack[hit_index]) continue;
+ hit_index++;
+ }
+ branch.expression = branch.expression.transform(scanner);
+ if (side_effects || !replace_all) break;
+ }
+ }
+ abort = true;
+ return node;
+ }
+ }
+
function extract_args() {
var iife, fn = compressor.self();
if (fn instanceof AST_Function
@@ -1265,18 +1275,49 @@ merge(Compressor.prototype, {
hit_stack.pop();
}
- function find_stop(node, level) {
+ function find_stop(node, level, write_only) {
var parent = scanner.parent(level);
- if (parent instanceof AST_Binary) return node;
+ if (parent instanceof AST_Assign) {
+ if (write_only
+ && !(parent.left instanceof AST_PropAccess
+ || parent.left.name in lvalues)) {
+ return find_stop(parent, level + 1, write_only);
+ }
+ return node;
+ }
+ if (parent instanceof AST_Binary) {
+ if (write_only && (!lazy_op(parent.operator) || parent.left === node)) {
+ return find_stop(parent, level + 1, write_only);
+ }
+ return node;
+ }
if (parent instanceof AST_Call) return node;
if (parent instanceof AST_Case) return node;
- if (parent instanceof AST_Conditional) return node;
- if (parent instanceof AST_Definitions) return find_stop(parent, level + 1);
- if (parent instanceof AST_Exit) return node;
- if (parent instanceof AST_If) return node;
+ if (parent instanceof AST_Conditional) {
+ if (write_only && parent.condition === node) {
+ return find_stop(parent, level + 1, write_only);
+ }
+ return node;
+ }
+ if (parent instanceof AST_Definitions) {
+ return find_stop(parent, level + 1, true);
+ }
+ if (parent instanceof AST_Exit) {
+ return write_only ? find_stop(parent, level + 1, write_only) : node;
+ }
+ if (parent instanceof AST_If) {
+ if (write_only && parent.condition === node) {
+ return find_stop(parent, level + 1, write_only);
+ }
+ return node;
+ }
if (parent instanceof AST_IterationStatement) return node;
- if (parent instanceof AST_Sequence) return find_stop(parent, level + 1);
- if (parent instanceof AST_SimpleStatement) return find_stop(parent, level + 1);
+ if (parent instanceof AST_Sequence) {
+ return find_stop(parent, level + 1, parent.tail_node() !== node);
+ }
+ if (parent instanceof AST_SimpleStatement) {
+ return find_stop(parent, level + 1, true);
+ }
if (parent instanceof AST_Switch) return node;
if (parent instanceof AST_VarDef) return node;
return null;
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 948389b..a2571c2 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -4249,3 +4249,137 @@ issue_2858: {
}
expect_stdout: "undefined"
}
+
+cond_branch_1: {
+ options = {
+ collapse_vars: true,
+ sequences: true,
+ unused: true,
+ }
+ input: {
+ function f1(b, c) {
+ var log = console.log;
+ var a = ++c;
+ if (b) b++;
+ log(a, b);
+ }
+ function f2(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b && b++;
+ log(a, b);
+ }
+ function f3(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b ? b++ : b--;
+ log(a, b);
+ }
+ f1(1, 2);
+ f2(3, 4);
+ f3(5, 6);
+ }
+ expect: {
+ function f1(b, c) {
+ var log = console.log;
+ if (b) b++;
+ log(++c, b);
+ }
+ function f2(b, c) {
+ var log = console.log;
+ b && b++,
+ log(++c, b);
+ }
+ function f3(b, c) {
+ var log = console.log;
+ b ? b++ : b--,
+ log(++c, b);
+ }
+ f1(1, 2),
+ f2(3, 4),
+ f3(5, 6);
+ }
+ expect_stdout: [
+ "3 2",
+ "5 4",
+ "7 6",
+ ]
+}
+
+cond_branch_2: {
+ options = {
+ collapse_vars: true,
+ sequences: true,
+ unused: true,
+ }
+ input: {
+ function f1(b, c) {
+ var log = console.log;
+ var a = ++c;
+ if (b) b += a;
+ log(a, b);
+ }
+ function f2(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b && (b += a);
+ log(a, b);
+ }
+ function f3(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b ? b += a : b--;
+ log(a, b);
+ }
+ f1(1, 2);
+ f2(3, 4);
+ f3(5, 6);
+ }
+ expect: {
+ function f1(b, c) {
+ var log = console.log;
+ var a = ++c;
+ if (b) b += a;
+ log(a, b);
+ }
+ function f2(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b && (b += a),
+ log(a, b);
+ }
+ function f3(b, c) {
+ var log = console.log;
+ var a = ++c;
+ b ? b += a : b--,
+ log(a, b);
+ }
+ f1(1, 2),
+ f2(3, 4),
+ f3(5, 6);
+ }
+ expect_stdout: [
+ "3 4",
+ "5 8",
+ "7 12",
+ ]
+}
+
+cond_branch_switch: {
+ options = {
+ collapse_vars: true,
+ }
+ input: {
+ var c = 0;
+ if (c = 1 + c, 0) switch (c = 1 + c) {
+ }
+ console.log(c);
+ }
+ expect: {
+ var c = 0;
+ if (c = 1 + c, 0) switch (c = 1 + c) {
+ }
+ console.log(c);
+ }
+ expect_stdout: "1"
+}
--
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