8129962: Investigate performance improvements in langtools combo tests

New combo API that runs all combo instances in a shared javac context (whenever possible).

Reviewed-by: jjg, jlahoda, vromero

langtools/test/tools/javac/lib/combo/ComboInstance.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2015, 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 combo;
+
+import javax.tools.StandardJavaFileManager;
+import java.util.Optional;
+
+/**
+ * This class is the common superclass of all combo test instances. It defines few helper methods
+ * to build compilation tasks using the shared context object, as well as entry points for
+ * signalling test failures.
+ */
+public abstract class ComboInstance<X extends ComboInstance<X>> {
+
+    /** The test instance result status. */
+    private ResultStatus resultStatus = ResultStatus.PASSED;
+
+    /** The test instance execution environment. */
+    private ComboTestHelper<X>.Env env;
+
+    /**
+     * Entry point for executing a combo test instance; first, the test environment is saved
+     * in the corresponding field, then the instance is run (see {@link ComboInstance#doWork()}.
+     * During execution, the result status will be updated to match the test outcome.
+     */
+    final void run(ComboTestHelper<X>.Env env) {
+        try {
+            this.env = env;
+            doWork();
+            if (resultStatus.isSuccess()) {
+                env.info().passCount++;
+            }
+        } catch (Throwable ex) {
+            resultStatus = ResultStatus.ERROR;
+            env.info().errCount++;
+            env.info().lastError = Optional.of(ex);
+        } finally {
+            this.env = null;
+        }
+    }
+
+    /**
+     * Retrieve a unique ID associated with this test instance.
+     */
+    public int id() {
+        return env.info().comboCount;
+    }
+
+    /**
+     * Retrieve shared file manager.
+     */
+    public StandardJavaFileManager fileManager() {
+        return env.fileManager();
+    }
+
+    /**
+     * Create a new compilation task using shared compilation context.
+     */
+    protected ComboTask newCompilationTask() {
+        return new ComboTask(env);
+    }
+
+    /**
+     * Main test execution entry point; subclasses must implement this method to define the test
+     * logic.
+     */
+    protected abstract void doWork() throws Throwable;
+
+    /**
+     * Report a test failure.
+     */
+    protected void fail() {
+        //dump some default info (such as dimension bindings)
+        fail("Combo instance failed; " + env.bindings);
+    }
+
+    /**
+     * Report a test failure with corresponding failure message.
+     */
+    protected void fail(String msg) {
+        resultStatus = ResultStatus.FAILED;
+        env.info().failCount++;
+        env.info().lastFailure = Optional.of(msg);
+    }
+
+    /**
+     * The status associated with this test instance execution.
+     */
+    enum ResultStatus {
+        /** Test passed. */
+        PASSED(true),
+        /** Test failed. */
+        FAILED(false),
+        /** Test thrown unexpected error/exception. */
+        ERROR(false);
+
+        boolean success;
+
+        ResultStatus(boolean success) {
+            this.success = success;
+        }
+
+        boolean isSuccess() {
+            return success;
+        }
+    }
+}