From 3ff05d1c5d0615aa6f04ab47408e2b69551c6e86 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Wed, 4 Mar 2020 12:14:25 +0300
Subject: [PATCH] Eliminate redundant try/catches in generated bytecode for
 enums

---
 .../model/PreOptimizingClassHolderSource.java |  3 +
 .../NoSuchFieldCatchElimination.java          | 56 +++++++++++++++++++
 core/src/main/java/org/teavm/vm/TeaVM.java    |  2 +-
 3 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 core/src/main/java/org/teavm/model/transformation/NoSuchFieldCatchElimination.java

diff --git a/core/src/main/java/org/teavm/model/PreOptimizingClassHolderSource.java b/core/src/main/java/org/teavm/model/PreOptimizingClassHolderSource.java
index 6b0852601..80c8998ed 100644
--- a/core/src/main/java/org/teavm/model/PreOptimizingClassHolderSource.java
+++ b/core/src/main/java/org/teavm/model/PreOptimizingClassHolderSource.java
@@ -20,6 +20,7 @@ import java.util.Map;
 import java.util.function.Function;
 import org.teavm.model.optimization.GlobalValueNumbering;
 import org.teavm.model.optimization.UnusedVariableElimination;
+import org.teavm.model.transformation.NoSuchFieldCatchElimination;
 
 public class PreOptimizingClassHolderSource implements ClassHolderSource {
     private ClassHolderSource innerClassSource;
@@ -48,8 +49,10 @@ public class PreOptimizingClassHolderSource implements ClassHolderSource {
         if (cls == null) {
             return cls;
         }
+        NoSuchFieldCatchElimination noSuchFieldCatchElimination = new NoSuchFieldCatchElimination();
         for (MethodHolder method : cls.getMethods()) {
             if (method.getProgram() != null) {
+                noSuchFieldCatchElimination.apply(method.getProgram());
                 new GlobalValueNumbering(true).optimize(method.getProgram());
                 new UnusedVariableElimination().optimize(method, method.getProgram());
             }
diff --git a/core/src/main/java/org/teavm/model/transformation/NoSuchFieldCatchElimination.java b/core/src/main/java/org/teavm/model/transformation/NoSuchFieldCatchElimination.java
new file mode 100644
index 000000000..05bd3e71e
--- /dev/null
+++ b/core/src/main/java/org/teavm/model/transformation/NoSuchFieldCatchElimination.java
@@ -0,0 +1,56 @@
+/*
+ *  Copyright 2020 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.model.transformation;
+
+import org.teavm.model.BasicBlock;
+import org.teavm.model.Incoming;
+import org.teavm.model.Phi;
+import org.teavm.model.Program;
+import org.teavm.model.TryCatchBlock;
+import org.teavm.model.optimization.UnreachableBasicBlockEliminator;
+
+public class NoSuchFieldCatchElimination {
+    private UnreachableBasicBlockEliminator blockEliminator = new UnreachableBasicBlockEliminator();
+
+    public void apply(Program program) {
+        boolean modified = false;
+        for (BasicBlock block : program.getBasicBlocks()) {
+            for (int i = 0; i < block.getTryCatchBlocks().size(); ++i) {
+                TryCatchBlock tryCatch = block.getTryCatchBlocks().get(i);
+                if (tryCatch.getExceptionType() != null
+                        && tryCatch.getExceptionType().equals(NoSuchFieldError.class.getName())) {
+                    updateTryCatchHandler(tryCatch);
+                    block.getTryCatchBlocks().remove(i--);
+                    modified = true;
+                }
+            }
+        }
+        if (modified) {
+            blockEliminator.optimize(program);
+        }
+    }
+
+    private void updateTryCatchHandler(TryCatchBlock tryCatch) {
+        for (Phi phi : tryCatch.getHandler().getPhis()) {
+            for (int i = 0; i < phi.getIncomings().size(); ++i) {
+                Incoming incoming = phi.getIncomings().get(i);
+                if (incoming.getSource() == tryCatch.getProtectedBlock()) {
+                    phi.getIncomings().remove(i--);
+                }
+            }
+        }
+    }
+}
diff --git a/core/src/main/java/org/teavm/vm/TeaVM.java b/core/src/main/java/org/teavm/vm/TeaVM.java
index 10c885dd6..07fcba50c 100644
--- a/core/src/main/java/org/teavm/vm/TeaVM.java
+++ b/core/src/main/java/org/teavm/vm/TeaVM.java
@@ -769,7 +769,7 @@ public class TeaVM implements TeaVMHost, ServiceRepository {
             //optimizations.add(new LoopInversion());
             optimizations.add(new LoopInvariantMotion());
         }
-        if (optimizationLevel.ordinal() >= TeaVMOptimizationLevel.FULL.ordinal()) {
+        if (optimizationLevel.ordinal() >= TeaVMOptimizationLevel.ADVANCED.ordinal()) {
             optimizations.add(new RepeatedFieldReadElimination());
         }
         optimizations.add(new GlobalValueNumbering(optimizationLevel == TeaVMOptimizationLevel.SIMPLE));