1 files changed, 110 insertions, 0 deletions
diff --git a/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchFilter.java b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchFilter.java
new file mode 100644
index 00000000..a78e253e
--- /dev/null
+++ b/org.jacoco.core/src/org/jacoco/core/internal/analysis/filter/StringSwitchFilter.java
@@ -0,0 +1,110 @@
+/*******************************************************************************
+ * Copyright (c) 2009, 2021 Mountainminds GmbH & Co. KG and Contributors
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Evgeny Mandrikov - initial API and implementation
+ *
+ *******************************************************************************/
+package org.jacoco.core.internal.analysis.filter;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.JumpInsnNode;
+import org.objectweb.asm.tree.LabelNode;
+import org.objectweb.asm.tree.LookupSwitchInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.TableSwitchInsnNode;
+import org.objectweb.asm.tree.VarInsnNode;
+
+/**
+ * Filters code that is generated by ECJ for a <code>switch</code> statement
+ * with a <code>String</code> and by Kotlin compiler 1.5 and above for a
+ * <code>when</code> expression with a <code>String</code>.
+ */
+public final class StringSwitchFilter implements IFilter {
+
+	public void filter(final MethodNode methodNode,
+			final IFilterContext context, final IFilterOutput output) {
+		final Matcher matcher = new Matcher();
+		for (final AbstractInsnNode i : methodNode.instructions) {
+			matcher.match(i, output);
+		}
+	}
+
+	private static class Matcher extends AbstractMatcher {
+		public void match(final AbstractInsnNode start,
+				final IFilterOutput output) {
+
+			if (start.getOpcode() != /* ECJ */ Opcodes.ASTORE
+					&& start.getOpcode() != /* Kotlin */ Opcodes.ALOAD) {
+				return;
+			}
+			cursor = start;
+			nextIsInvoke(Opcodes.INVOKEVIRTUAL, "java/lang/String", "hashCode",
+					"()I");
+			nextIsSwitch();
+			if (cursor == null) {
+				return;
+			}
+			vars.put("s", (VarInsnNode) start);
+
+			final AbstractInsnNode s = cursor;
+			final int hashCodes;
+			final LabelNode defaultLabel;
+			if (s.getOpcode() == Opcodes.LOOKUPSWITCH) {
+				final LookupSwitchInsnNode lookupSwitch = (LookupSwitchInsnNode) cursor;
+				defaultLabel = lookupSwitch.dflt;
+				hashCodes = lookupSwitch.labels.size();
+			} else {
+				final TableSwitchInsnNode tableSwitch = (TableSwitchInsnNode) cursor;
+				defaultLabel = tableSwitch.dflt;
+				hashCodes = tableSwitch.labels.size();
+			}
+
+			if (hashCodes == 0) {
+				return;
+			}
+
+			final Set<AbstractInsnNode> replacements = new HashSet<AbstractInsnNode>();
+			replacements.add(skipNonOpcodes(defaultLabel));
+
+			for (int i = 0; i < hashCodes; i++) {
+				while (true) {
+					nextIsVar(Opcodes.ALOAD, "s");
+					nextIs(Opcodes.LDC);
+					nextIsInvoke(Opcodes.INVOKEVIRTUAL, "java/lang/String",
+							"equals", "(Ljava/lang/Object;)Z");
+					// jump to case
+					nextIs(Opcodes.IFNE);
+					if (cursor == null) {
+						return;
+					}
+
+					replacements
+							.add(skipNonOpcodes(((JumpInsnNode) cursor).label));
+
+					if (cursor.getNext().getOpcode() == Opcodes.GOTO) {
+						// end of comparisons for same hashCode
+						// jump to default
+						nextIs(Opcodes.GOTO);
+						break;
+					} else if (cursor.getNext() == defaultLabel) {
+						break;
+					}
+				}
+			}
+
+			output.ignore(s.getNext(), cursor);
+			output.replaceBranches(s, replacements);
+		}
+	}
+
+}