From 7c1bb6392e908d860d4629881c99f6ab241ed9da Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Mon, 6 Nov 2023 15:15:00 -0800
Subject: [PATCH] Fix support for JS destructuring in acorn optimizer pass

Fixes: #20631
---
 test/optimizer/JSDCE-defaultArg-output.js |  6 ++++--
 test/optimizer/JSDCE-defaultArg.js        |  5 +++--
 tools/acorn-optimizer.js                  | 16 ++++++++++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/test/optimizer/JSDCE-defaultArg-output.js b/test/optimizer/JSDCE-defaultArg-output.js
index c8e64b44e4e19..5216c9b3bbcb6 100644
--- a/test/optimizer/JSDCE-defaultArg-output.js
+++ b/test/optimizer/JSDCE-defaultArg-output.js
@@ -1,7 +1,9 @@
 var usedAsDefaultArg = 42;
 
-function g(a, b = usedAsDefaultArg) {
- return a + b + 1;
+var usedAsDefaultArg2 = [ 1, 2 ];
+
+function g({notUsed: notUsed}, a, b = usedAsDefaultArg, [c, d] = usedAsDefaultArg2) {
+ return a + b + notUsed + 1;
 }
 
 Module["g"] = g;
diff --git a/test/optimizer/JSDCE-defaultArg.js b/test/optimizer/JSDCE-defaultArg.js
index 4ec7c74bab693..06a79b3f50a87 100644
--- a/test/optimizer/JSDCE-defaultArg.js
+++ b/test/optimizer/JSDCE-defaultArg.js
@@ -1,9 +1,10 @@
 var usedAsDefaultArg = 42;
+var usedAsDefaultArg2 = [1,2];
 var notUsed = 43;
 
 // exported
-function g(a, b = usedAsDefaultArg) {
-  return a+b+1;
+function g({notUsed}, a, b = usedAsDefaultArg, [c, d] = usedAsDefaultArg2) {
+  return a+b+notUsed+1;
 }
 
 Module['g'] = g;
diff --git a/tools/acorn-optimizer.js b/tools/acorn-optimizer.js
index 2d97919f7959c..1858c627cd6df 100755
--- a/tools/acorn-optimizer.js
+++ b/tools/acorn-optimizer.js
@@ -379,6 +379,22 @@ function runJSDCE(ast, aggressive) {
           c(param.right);
           param = param.left;
         }
+        if (param.type === 'ArrayPattern') {
+          for (var elem of param.elements) {
+            const name = elem.name;
+            ensureData(scope, name).def = 1;
+            scope[name].param = 1;
+          }
+          return;
+        }
+        if (param.type === 'ObjectPattern') {
+          for (var prop of param.properties) {
+            const name = prop.key.name;
+            ensureData(scope, name).def = 1;
+            scope[name].param = 1;
+          }
+          return;
+        }
         assert(param.type === 'Identifier', param.type);
         const name = param.name;
         ensureData(scope, name).def = 1;