perf: optimize unminify

up to 14x faster string merging
j4k0xb · Apr 19, 2024 · 78f8e30 · 78f8e30
1 parent d042684
commit 78f8e30
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Showing 5 changed files with 37 additions and 69 deletions.
diff --git a/packages/webcrack/src/unminify/test/number-expressions.test.ts b/packages/webcrack/src/unminify/test/number-expressions.test.ts
@@ -22,5 +22,5 @@ test('keep divisions if it results in a decimal number', () =>
     '(-0x152f + 0x1281 * -0x1 + -0x18 * -0x1d1) / (0x83 * -0x1a + -0x19ea + 0x5f * 0x6a)',
   ).toMatchInlineSnapshot('1000 / 30;'));
 
-test('ignore string results', () =>
-  expectJS('0x1021e + "test"').toMatchInlineSnapshot('0x1021e + "test";'));
+test('string and number concatenation', () =>
+  expectJS('0x1021e + "test"').toMatchInlineSnapshot('"66078test";'));
diff --git a/packages/webcrack/src/unminify/transforms/for-to-while.ts b/packages/webcrack/src/unminify/transforms/for-to-while.ts
@@ -11,9 +11,7 @@ export default {
           const { test, body, init, update } = path.node;
           if (init || update) return;
           path.replaceWith(
-            test
-              ? t.whileStatement(test, body)
-              : t.whileStatement(t.booleanLiteral(true), body),
+            t.whileStatement(test ?? t.booleanLiteral(true), body),
           );
           this.changes++;
         },

diff --git a/packages/webcrack/src/unminify/transforms/logical-to-if.ts b/packages/webcrack/src/unminify/transforms/logical-to-if.ts
@@ -1,31 +1,28 @@
 import { statement } from '@babel/template';
-import type * as t from '@babel/types';
-import * as m from '@codemod/matchers';
+import * as t from '@babel/types';
 import type { Transform } from '../../ast-utils';
 
 export default {
   name: 'logical-to-if',
   tags: ['safe'],
   visitor: () => {
-    const andMatcher = m.expressionStatement(m.logicalExpression('&&'));
-    const orMatcher = m.expressionStatement(m.logicalExpression('||'));
-
     const buildIf = statement`if (TEST) { BODY; }`;
     const buildIfNot = statement`if (!TEST) { BODY; }`;
 
     return {
       ExpressionStatement: {
         exit(path) {
           const expression = path.node.expression as t.LogicalExpression;
-          if (andMatcher.match(path.node)) {
+          if (!t.isLogicalExpression(expression)) return;
+          if (expression.operator === '&&') {
             path.replaceWith(
               buildIf({
                 TEST: expression.left,
                 BODY: expression.right,
               }),
             );
             this.changes++;
-          } else if (orMatcher.match(path.node)) {
+          } else if (expression.operator === '||') {
             path.replaceWith(
               buildIfNot({
                 TEST: expression.left,

diff --git a/packages/webcrack/src/unminify/transforms/merge-strings.ts b/packages/webcrack/src/unminify/transforms/merge-strings.ts
@@ -1,42 +1,31 @@
-import * as t from '@babel/types';
 import * as m from '@codemod/matchers';
 import type { Transform } from '../../ast-utils';
 
+// "a" + "b" -> "ab"
+// (a + "b") + "c" -> a + "bc"
+//  left ^      ^ right (path)
 export default {
   name: 'merge-strings',
   tags: ['safe'],
   visitor() {
-    const left = m.capture(m.stringLiteral(m.anyString()));
-    const right = m.capture(m.stringLiteral(m.anyString()));
+    const left = m.capture(m.stringLiteral());
+    const right = m.capture(m.stringLiteral());
 
-    const matcher = m.binaryExpression('+', left, right);
-    const nestedMatcher = m.binaryExpression(
+    const matcher = m.binaryExpression(
       '+',
-      m.binaryExpression('+', m.anything(), left),
+      m.or(left, m.binaryExpression('+', m.anything(), left)),
       right,
     );
 
     return {
       BinaryExpression: {
         exit(path) {
-          if (matcher.match(path.node)) {
-            // "a" + "b" -> "ab"
-            path.replaceWith(
-              t.stringLiteral(left.current!.value + right.current!.value),
-            );
-            this.changes++;
-          }
-        },
-      },
-      StringLiteral: {
-        exit(path) {
-          if (nestedMatcher.match(path.parent)) {
-            // (a + "b") + "c" -> a + "bc"
-            //  left ^      ^ right (path)
-            left.current!.value += right.current!.value;
-            path.remove();
-            this.changes++;
-          }
+          if (!matcher.match(path.node)) return;
+          left.current!.value += right.current!.value;
+          right.current!.value = ''; // Otherwise it concatenates multiple times for some reason
+          path.replaceWith(path.node.left);
+          path.skip();
+          this.changes++;
         },
       },
     };

diff --git a/packages/webcrack/src/unminify/transforms/number-expressions.ts b/packages/webcrack/src/unminify/transforms/number-expressions.ts
@@ -8,51 +8,35 @@ export default {
   visitor: () => ({
     'BinaryExpression|UnaryExpression': {
       exit(path) {
-        if (matcher.match(path.node)) {
-          const evaluated = path.evaluate();
-          if (evaluated.confident) {
-            // Heuristic: Simplifying a division that results in a non-integer probably doesn't increase readability
-            if (
-              path.node.type === 'BinaryExpression' &&
-              path.node.operator === '/' &&
-              !Number.isInteger(evaluated.value)
-            ) {
-              return;
-            }
-
-            path.replaceWith(t.valueToNode(evaluated.value));
-            path.skip();
-            this.changes++;
-          }
+        if (!matcher.match(path.node)) return;
+        const evaluated = path.evaluate();
+        if (
+          t.isBinaryExpression(path.node, { operator: '/' }) &&
+          !Number.isInteger(evaluated.value)
+        ) {
+          return;
         }
+        path.replaceWith(t.valueToNode(evaluated.value));
+        path.skip();
+        this.changes++;
       },
     },
   }),
 } satisfies Transform;
 
-const matcher: m.Matcher<t.Expression> = m.or(
-  m.binaryExpression(
-    m.or('+', '-', '*', '/'),
-    m.matcher((node) => matcher.match(node)),
-    m.matcher((node) => matcher.match(node)),
-  ),
+const matcher = m.or(
+  m.unaryExpression('-', m.or(m.stringLiteral(), m.numericLiteral())),
   m.binaryExpression(
-    '-',
+    m.or('+', '-', '/', '%', '*', '**', '&', '|', '>>', '>>>', '<<', '^'),
     m.or(
       m.stringLiteral(),
-      m.matcher((node) => matcher.match(node)),
+      m.numericLiteral(),
+      m.unaryExpression('-', m.numericLiteral()),
     ),
     m.or(
       m.stringLiteral(),
-      m.matcher((node) => matcher.match(node)),
-    ),
-  ),
-  m.unaryExpression(
-    '-',
-    m.or(
-      m.stringLiteral(),
-      m.matcher((node) => matcher.match(node)),
+      m.numericLiteral(),
+      m.unaryExpression('-', m.numericLiteral()),
     ),
   ),
-  m.numericLiteral(),
 );