8342806: Desugar capturing lambda in StringNameTable

Reviewed-by: mcimadamore, liach

src/jdk.compiler/share/classes/com/sun/tools/javac/util/StringNameTable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -62,7 +62,15 @@ public class StringNameTable extends Name.Table {
 
     @Override
     public Name fromString(String string) {
-        return this.nameMap.computeIfAbsent(string, s -> new NameImpl(this, intern ? s.intern() : s));
+        Name name = nameMap.get(string);
+        if (name == null) {
+            if (intern) {
+                string = string.intern();
+            }
+            name = new NameImpl(this, string);
+            nameMap.put(string, name);
+        }
+        return name;
     }
 
     @Override

test/micro/org/openjdk/bench/javax/tools/JavacNameTable.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.bench.javax.tools;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.annotations.Warmup;
+
+import javax.tools.JavaCompiler;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.StandardLocation;
+import javax.tools.ToolProvider;
+import java.io.IOException;
+import java.io.File;
+import java.net.URI;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+@Warmup(iterations = 5, time = 3, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 5, timeUnit = TimeUnit.SECONDS)
+@Fork(value = 2, jvmArgs = "-Xmx1g")
+public class JavacNameTable {
+
+    private List<JavaSourceFromString> compilationUnits;
+    private JavaCompiler compiler;
+    private StandardJavaFileManager fileManager;
+    private File classDir;
+
+    @Setup
+    public void prepare() throws IOException {
+
+        // Create a source file with lots of names
+        StringBuilder buf = new StringBuilder();
+        buf.append("class BigSource {\n");
+        for (int i = 0; i < 20000; i++) {
+            buf.append(String.format(
+                //"final String name%05d = \"some text #%5d\";\n", i, i));
+                "String name%05d;\n", i, i));
+        }
+        buf.append("}\n");
+        String bigSource = buf.toString();
+
+        compiler = ToolProvider.getSystemJavaCompiler();
+
+        fileManager = compiler.getStandardFileManager(null, null, null);
+        classDir = Files.createTempDirectory(
+          JavacNameTable.class.getName()).toFile();
+        fileManager.setLocation(StandardLocation.CLASS_OUTPUT,
+          Collections.singleton(classDir));
+
+        compilationUnits = new ArrayList<>();
+        compilationUnits.add(new JavaSourceFromString("BigSource", bigSource));
+    }
+
+    @TearDown
+    public void tearDown() {
+        for (File f : classDir.listFiles()) {
+            if (f.isFile()) {
+                f.delete();
+            } else {
+                throw new IllegalStateException("Unexpected non-file: " + f);
+            }
+        }
+        classDir.delete();
+    }
+
+    @Benchmark
+    public Boolean testSharedTable() throws Exception {
+        return testCompile(null);
+    }
+
+    @Benchmark
+    public Boolean testUnsharedTable() throws Exception {
+        return testCompile("-XDuseUnsharedTable=true");
+    }
+
+    @Benchmark
+    public Boolean testStringTable() throws Exception {
+        return testCompile("-XDuseStringTable=true");
+    }
+
+    @Benchmark
+    public Boolean testInternStringTable() throws Exception {
+        return testCompile("-XDinternStringTable=true");
+    }
+
+    public Boolean testCompile(String flag) throws Exception {
+        final List<String> options = flag != null ?
+          Collections.singletonList(flag) : null;
+        JavaCompiler.CompilationTask task = compiler.getTask(null, fileManager,
+          null, options, null, compilationUnits);
+        return task.call();
+    }
+
+    private static class JavaSourceFromString extends SimpleJavaFileObject {
+
+        private final String code;
+
+        JavaSourceFromString(String name, String code) {
+            super(URI.create("string:///"
+              + name.replace('.', '/') + Kind.SOURCE.extension), Kind.SOURCE);
+            this.code = code;
+        }
+
+        @Override
+        public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+            return code;
+        }
+    }
+}