[Enhanced Switch] Wasteful generation of switch ordinal mapping table

for enum switches that are dispatched via enumSwitch indy * Fixes eclipse-jdt#3447
srikanth-sankaran · Dec 13, 2024 · 585c0e4 · 585c0e4
1 parent 93d8dc5
commit 585c0e4
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Showing 2 changed files with 44 additions and 2 deletions.
diff --git a/...se.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/SwitchStatement.java b/...se.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/SwitchStatement.java
@@ -440,7 +440,7 @@ else if ((statement.bits & ASTNode.DocumentedFallthrough) == 0) // the case is n
 			}
 
 			final TypeBinding resolvedTypeBinding = this.expression.resolvedType;
-			if (resolvedTypeBinding.isEnum()) {
+			if (resolvedTypeBinding.isEnum() && !needPatternDispatchCopy()) {
 				final SourceTypeBinding sourceTypeBinding = currentScope.classScope().referenceContext.binding;
 				this.synthetic = sourceTypeBinding.addSyntheticMethodForSwitchEnum(resolvedTypeBinding, this);
 			}

diff --git a/....tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java b/....tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java
@@ -104,7 +104,7 @@ protected void runWarningTest(String[] testFiles, String expectedCompilerLog,
 		runner.runWarningTest();
 	}
 
-	private static void verifyClassFile(String expectedOutput, String classFileName, int mode)
+	private static void verifyClassFile(String expectedOutput, String unexpectedOutput, String classFileName, int mode)
 			throws IOException, ClassFormatException {
 		File f = new File(OUTPUT_DIR + File.separator + classFileName);
 		byte[] classFileBytes = org.eclipse.jdt.internal.compiler.util.Util.getFileByteContent(f);
@@ -118,6 +118,15 @@ private static void verifyClassFile(String expectedOutput, String classFileName,
 		if (index == -1) {
 			assertEquals("Wrong contents", expectedOutput, result);
 		}
+		if (unexpectedOutput != null) {
+			index = result.indexOf(unexpectedOutput);
+			assertTrue("Unexpected output found", index == -1);
+		}
+	}
+
+	private static void verifyClassFile(String expectedOutput, String classFileName, int mode)
+			throws IOException, ClassFormatException {
+		verifyClassFile(expectedOutput, null, classFileName, mode);
 	}
 	public void testIssue57_001() {
 		runConformTest(
@@ -9628,4 +9637,37 @@ public static void main(String[] args) {
 				"World--Check--Hello--Null--Default--\n" +
 				"Default--Null--Hello--Check--World--");
 	}
+
+	// https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3447
+	// [Enhanced Switch] Wasteful generation of switch ordinal mapping table for enum switches that are dispatched via enumSwitch indy
+	public void testIssue3447() throws Exception {
+		runConformTest(
+			new String[] {
+				"X.java",
+				"""
+				enum E {
+					A,
+					B,
+				}
+
+				public class X {
+					public static void main(String[] args) {
+						E e = E.A;
+						switch (e) {
+							case A :    System.out.println("A");
+									    break;
+							case B:     System.out.println("B");
+							            break;
+							case null : System.out.println("null");
+										break;
+						}
+					}
+				}
+				"""
+			},
+		 "A");
+		String expectedOutput = "8  invokedynamic 0 enumSwitch(E, int) : int [22]\n";
+		String unexpectedOutput = "static synthetic int[] $SWITCH_TABLE$E();\n";
+		SwitchPatternTest.verifyClassFile(expectedOutput, unexpectedOutput, "X.class", ClassFileBytesDisassembler.SYSTEM);
+	}
 }