From 93d7aca9e6af236cbbe0decc28dc9900b94ab8a8 Mon Sep 17 00:00:00 2001
From: Daniel Holle <dholle@hb.dhbw-stuttgart.de>
Date: Thu, 17 Aug 2023 14:23:19 +0200
Subject: [PATCH] Switch on Strings

---
 resources/bytecode/javFiles/SwitchString.jav       | 14 ++++++++++++++
 .../java/de/dhbwstuttgart/bytecode/Codegen.java    | 14 ++++++--------
 .../typeinference/typeAlgo/TYPEStmt.java           |  9 +++++++--
 src/test/java/TestComplete.java                    | 14 ++++++++++++++
 4 files changed, 41 insertions(+), 10 deletions(-)
 create mode 100644 resources/bytecode/javFiles/SwitchString.jav

diff --git a/resources/bytecode/javFiles/SwitchString.jav b/resources/bytecode/javFiles/SwitchString.jav
new file mode 100644
index 00000000..e8758c25
--- /dev/null
+++ b/resources/bytecode/javFiles/SwitchString.jav
@@ -0,0 +1,14 @@
+import java.lang.Integer;
+import java.lang.String;
+import java.lang.Object;
+
+public class SwitchString {
+    main(o) {
+        return switch (o) {
+        case "AaAaAa" -> 1; // These two have the same hash code!
+        case "AaAaBB" -> 2;
+        case "test", "TEST" -> 3;
+        default -> 4;
+        };
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/de/dhbwstuttgart/bytecode/Codegen.java b/src/main/java/de/dhbwstuttgart/bytecode/Codegen.java
index 73b4ba78..5a758899 100644
--- a/src/main/java/de/dhbwstuttgart/bytecode/Codegen.java
+++ b/src/main/java/de/dhbwstuttgart/bytecode/Codegen.java
@@ -1111,21 +1111,19 @@ public class Codegen {
         var mt = MethodType.methodType(CallSite.class, MethodHandles.Lookup.class, String.class, MethodType.class, Object[].class);
         var bootstrap = new Handle(H_INVOKESTATIC, "java/lang/runtime/SwitchBootstraps", "typeSwitch", mt.toMethodDescriptorString(), false);
 
-        var types = new Object[aSwitch.cases().size()];
-        for (var i = 0; i < types.length; i++) {
-            var cse = aSwitch.cases().get(i);
-            var label = cse.labels().get(0);
+        var types = new ArrayList<Object>(aSwitch.cases().size());
+        for (var cse : aSwitch.cases()) for (var label : cse.labels()) {
             if (label instanceof SimplePattern || label instanceof ComplexPattern)
-                types[i] = Type.getObjectType(label.type().getInternalName());
+                types.add(Type.getObjectType(label.type().getInternalName()));
             else if (label instanceof TargetLiteral lit)
-                types[i] = lit.value();
+                types.add(lit.value());
             else if (label instanceof Guard guard)
-                types[i] = Type.getObjectType(guard.inner().type().getInternalName());
+                types.add(Type.getObjectType(guard.inner().type().getInternalName()));
             // TODO Same here we need to evaluate constant;
             else throw new NotImplementedException();
         }
 
-        mv.visitInvokeDynamicInsn("typeSwitch", "(Ljava/lang/Object;I)I", bootstrap, types);
+        mv.visitInvokeDynamicInsn("typeSwitch", "(Ljava/lang/Object;I)I", bootstrap, types.toArray());
 
         var caseLabels = new Label[aSwitch.cases().size()];
         var labels = new Label[aSwitch.cases().stream().mapToInt(c -> c.labels().size()).sum()];
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java b/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
index 7f1a9159..88912144 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/typeAlgo/TYPEStmt.java
@@ -735,8 +735,13 @@ public class TYPEStmt implements StatementVisitor {
     public void visit(Switch switchStmt) {
         switchStack.push(switchStmt);
         for (var child : switchStmt.getBlocks()) {
-            for (var label : child.getLabels()) if (label.getExpression() instanceof Pattern)
-                constraintsSet.addUndConstraint(new Pair(label.getExpression().getType(), switchStmt.getSwitch().getType(), PairOperator.SMALLERDOT));
+            for (var label : child.getLabels()) {
+                if (label.getExpression() instanceof Pattern) {
+                    constraintsSet.addUndConstraint(new Pair(label.getExpression().getType(), switchStmt.getSwitch().getType(), PairOperator.SMALLERDOT));
+                } else {
+                    constraintsSet.addUndConstraint(new Pair(label.getType(), switchStmt.getSwitch().getType(), PairOperator.SMALLERDOT));
+                }
+            }
 
             child.accept(this);
             constraintsSet.addUndConstraint(new Pair(child.getType(), switchStmt.getType(), PairOperator.SMALLERDOT));
diff --git a/src/test/java/TestComplete.java b/src/test/java/TestComplete.java
index 1d76bc68..5f3d592e 100644
--- a/src/test/java/TestComplete.java
+++ b/src/test/java/TestComplete.java
@@ -670,4 +670,18 @@ public class TestComplete {
         assertEquals(swtch.invoke(instance, 50), 50);
         assertEquals(swtch.invoke(instance, "Some string"), 0);
     }
+
+    @Test
+    public void testStringSwitch() throws Exception {
+        var classFiles = generateClassFiles(new ByteArrayClassLoader(), "SwitchString.jav");
+        var clazz = classFiles.get("SwitchString");
+        var instance = clazz.getDeclaredConstructor().newInstance();
+        var main = clazz.getDeclaredMethod("main", String.class);
+
+        assertEquals(main.invoke(instance, "AaAaAa"), 1);
+        assertEquals(main.invoke(instance, "AaAaBB"), 2);
+        assertEquals(main.invoke(instance, "test"), 3);
+        assertEquals(main.invoke(instance, "TEST"), 3);
+        assertEquals(main.invoke(instance, "awawa"), 4);
+    }
 }