Modify LivenessAnaylizer to not rely on dominator tree. Fix possible

name clash between virtual methods and fields. Remove tests incompatible
between JDK7 and JDK8

teavm-core/src/main/java/org/teavm/codegen/DefaultAliasProvider.java

@@ -15,6 +15,8 @@
  */
 package org.teavm.codegen;
 
+import java.util.HashSet;
+import java.util.Set;
 import org.teavm.model.FieldReference;
 import org.teavm.model.MethodDescriptor;
 import org.teavm.model.MethodReference;
@@ -26,6 +28,7 @@ import org.teavm.model.MethodReference;
 public class DefaultAliasProvider implements AliasProvider {
     private int lastSuffix;
     private int lastVirtualSuffix;
+    private Set<String> usedAliases = new HashSet<>();
 
     @Override
     public String getAlias(String cls) {
@@ -58,7 +61,11 @@ public class DefaultAliasProvider implements AliasProvider {
         } else if (alias.equals("<clinit>")) {
             alias = "$clinit";
         }
-        return alias + lastVirtualSuffix++;
+        String result;
+        do {
+            result = alias + lastVirtualSuffix++;
+        } while (!usedAliases.add(result));
+        return result;
     }
 
     @Override
@@ -74,7 +81,11 @@ public class DefaultAliasProvider implements AliasProvider {
 
     @Override
     public String getAlias(FieldReference field) {
-        return field.getFieldName() + (lastSuffix++);
+        String result;
+        do {
+            result = field.getFieldName() + lastSuffix++;
+        } while (!usedAliases.add(result));
+        return result;
     }
 
     @Override

teavm-core/src/main/java/org/teavm/codegen/MinifyingAliasProvider.java

@@ -15,6 +15,8 @@
  */
 package org.teavm.codegen;
 
+import java.util.HashSet;
+import java.util.Set;
 import org.teavm.model.FieldReference;
 import org.teavm.model.MethodDescriptor;
 import org.teavm.model.MethodReference;
@@ -29,10 +31,15 @@ public class MinifyingAliasProvider implements AliasProvider {
     private static String startVirtualLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
     private int lastSuffix;
     private int lastVirtual;
+    private Set<String> usedAliases = new HashSet<>();
 
     @Override
     public String getAlias(FieldReference field) {
-        return getNewAlias(lastVirtual++, startVirtualLetters);
+        String result;
+        do {
+            result = getNewAlias(lastVirtual++, startVirtualLetters);
+        } while (!usedAliases.add(result));
+        return result;
     }
 
     @Override
@@ -42,7 +49,11 @@ public class MinifyingAliasProvider implements AliasProvider {
 
     @Override
     public String getAlias(MethodDescriptor method) {
-        return getNewAlias(lastVirtual++, startVirtualLetters);
+        String result;
+        do {
+            result = getNewAlias(lastVirtual++, startVirtualLetters);
+        } while (!usedAliases.add(result));
+        return result;
     }
 
     @Override

teavm-core/src/main/java/org/teavm/model/util/LivenessAnalyzer.java

@@ -19,7 +19,6 @@ import java.util.ArrayDeque;
 import java.util.BitSet;
 import java.util.Deque;
 import org.teavm.common.Graph;
-import org.teavm.common.GraphUtils;
 import org.teavm.model.*;
 
 /**
@@ -28,8 +27,6 @@ import org.teavm.model.*;
  */
 public class LivenessAnalyzer {
     private BitSet[] liveVars;
-    private int[] domLeft;
-    private int[] domRight;
 
     public boolean liveIn(int block, int var) {
         return liveVars[block].get(var);
@@ -41,7 +38,6 @@ public class LivenessAnalyzer {
 
     public void analyze(Program program) {
         Graph cfg = ProgramUtils.buildControlFlowGraph(program);
-        computeDomLeftRight(GraphUtils.buildDominatorGraph(GraphUtils.buildDominatorTree(cfg), cfg.size()));
         liveVars = new BitSet[cfg.size()];
         for (int i = 0; i < liveVars.length; ++i) {
             liveVars[i] = new BitSet(program.basicBlockCount());
@@ -84,7 +80,7 @@ public class LivenessAnalyzer {
 
         while (!stack.isEmpty()) {
             Task task = stack.pop();
-            if (liveVars[task.block].get(task.var) || !dominates(definitions[task.var], task.block)) {
+            if (liveVars[task.block].get(task.var) || definitions[task.var] == task.block) {
                 continue;
             }
             liveVars[task.block].set(task.var, true);
@@ -97,35 +93,6 @@ public class LivenessAnalyzer {
         }
     }
 
-    private void computeDomLeftRight(Graph domGraph) {
-        domLeft = new int[domGraph.size()];
-        domRight = new int[domGraph.size()];
-        int index = 1;
-        int[] stack = new int[domGraph.size() * 2];
-        int top = 0;
-        for (int i = domGraph.size() - 1; i >= 0; --i) {
-            if (domGraph.incomingEdgesCount(i) == 0) {
-                stack[top++] = i;
-            }
-        }
-        while (top > 0) {
-            int v = stack[--top];
-            if (domLeft[v] == 0) {
-                domLeft[v] = index++;
-                stack[top++] = v;
-                for (int succ : domGraph.outgoingEdges(v)) {
-                    stack[top++] = succ;
-                }
-            } else if (domRight[v] == 0) {
-                domRight[v] = index++;
-            }
-        }
-    }
-
-    private boolean dominates(int a, int b) {
-        return domLeft[a] < domLeft[b] && domRight[a] > domRight[b];
-    }
-
     private static class Task {
         int block;
         int var;

teavm-tests/src/test/java/org/teavm/classlib/java/nio/charset/UTF8Test.java

@@ -93,25 +93,6 @@ public class UTF8Test {
         assertEquals("a\uFFFDbb", new String(result));
     }
 
-    @Test
-    public void replaceDecodedSurrogate() {
-        Charset charset = Charset.forName("UTF-8");
-        CharBuffer buffer = charset.decode(ByteBuffer.wrap(new byte[] { 97, (byte)0xED, (byte)0xA0, (byte)0x80, 98 }));
-        char[] result = new char[buffer.remaining()];
-        buffer.get(result);
-        assertEquals("a\uFFFDb", new String(result));
-    }
-
-    @Test
-    public void replaceDecodedSurrogatePair() {
-        Charset charset = Charset.forName("UTF-8");
-        CharBuffer buffer = charset.decode(ByteBuffer.wrap(new byte[] { 97, (byte)0xED, (byte)0xA0, (byte)0x80,
-                (byte)0xED, (byte)0xBF, (byte)0xBF, 98 }));
-        char[] result = new char[buffer.remaining()];
-        buffer.get(result);
-        assertEquals("a\uFFFD\uFFFDb", new String(result));
-    }
-
     @Test
     public void decodeLongUTF8ByteArray() throws UnsupportedEncodingException {
         byte[] bytes = new byte[16384];