Feature/array spread (#447)

* Implements compilation of arrays with spreading * Implements test cases for arrays with spreading
googleprojectzero · Sep 30, 2024 · 0e20cd5 · 0e20cd5
1 parent d9b7550
commit 0e20cd5
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Showing 2 changed files with 39 additions and 4 deletions.
diff --git a/Sources/Fuzzilli/Compiler/Compiler.swift b/Sources/Fuzzilli/Compiler/Compiler.swift
@@ -833,17 +833,29 @@ public class JavaScriptCompiler {
         case .arrayExpression(let arrayExpression):
             var elements = [Variable]()
             var undefined: Variable? = nil
+            var spreads = [Bool]()
             for elem in arrayExpression.elements {
                 if elem.expression == nil {
                     if undefined == nil {
                         undefined = emit(LoadUndefined()).output
                     }
                     elements.append(undefined!)
+                    spreads.append(false)
                 } else {
-                    elements.append(try compileExpression(elem))
+                    if case .spreadElement(let spreadElement) = elem.expression {
+                        elements.append(try compileExpression(spreadElement.argument))
+                        spreads.append(true)
+                    } else {
+                        elements.append(try compileExpression(elem))
+                        spreads.append(false)
+                    }
                 }
             }
-            return emit(CreateArray(numInitialValues: elements.count), withInputs: elements).output
+            if spreads.contains(true) {
+                return emit(CreateArrayWithSpread(spreads: spreads), withInputs: elements).output
+            } else {
+                return emit(CreateArray(numInitialValues: elements.count), withInputs: elements).output
+            }
 
         case .functionExpression(let functionExpression):
             let parameters = convertParameters(functionExpression.parameters)

diff --git a/Tests/FuzzilliTests/CompilerTests/spreading.js b/Tests/FuzzilliTests/CompilerTests/spreading.js
@@ -6,7 +6,7 @@ function foo(a, b, c) {
   output(c);
 }
 
-let a = [1,2,3,4];
+let a = [1, 2, 3, 4];
 
 foo(...a);
 foo(100, ...a);
@@ -24,4 +24,27 @@ o.foo(100, ...a);
 o.foo(100, 101, ...a);
 o.foo(100, 101, 102, ...a);
 
-// TODO also add tests for spreading in array literals
+// Array spreading tests
+let array1 = [10, 20, 30];
+let array2 = [...array1];
+
+output(array1);
+output(array2);
+
+array1[0] = 100;
+output(array1);
+output(array2);
+
+let combinedArray = [5, ...array1, 50];
+output(combinedArray);
+
+// Spread with array-like objects
+function testArguments() {
+  let argsArray = [...arguments];
+  output(argsArray);
+}
+
+testArguments(1, 2, 3);
+
+let nestedArray = [...[...[1, 2, 3]], ...[4, 5]];
+output(nestedArray);