/*

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 * 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.

 *

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/**

 * @test

 * @bug 8051344

 * @summary Force OSR compilation with non-empty stack at the OSR entry point.

 * @modules java.base/jdk.internal.org.objectweb.asm

 * @run main/othervm -XX:CompileCommand=compileonly,TestCase::test

 *                   compiler.osr.TestOSRWithNonEmptyStack

 */

package compiler.osr;

import jdk.internal.org.objectweb.asm.ClassWriter;

import jdk.internal.org.objectweb.asm.Label;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import java.lang.reflect.Constructor;

import java.lang.reflect.Method;

import static jdk.internal.org.objectweb.asm.Opcodes.ACC_PUBLIC;

import static jdk.internal.org.objectweb.asm.Opcodes.ALOAD;

import static jdk.internal.org.objectweb.asm.Opcodes.DUP;

import static jdk.internal.org.objectweb.asm.Opcodes.IADD;

import static jdk.internal.org.objectweb.asm.Opcodes.ICONST_0;

import static jdk.internal.org.objectweb.asm.Opcodes.ICONST_1;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPLT;

import static jdk.internal.org.objectweb.asm.Opcodes.ILOAD;

import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESPECIAL;

import static jdk.internal.org.objectweb.asm.Opcodes.ISTORE;

import static jdk.internal.org.objectweb.asm.Opcodes.POP;

import static jdk.internal.org.objectweb.asm.Opcodes.RETURN;

public class TestOSRWithNonEmptyStack extends ClassLoader {

    private static final int CLASS_FILE_VERSION = 52;

    private static final String CLASS_NAME = "TestCase";

    private static final String METHOD_NAME = "test";

    private static final int ITERATIONS = 1_000_000;

    private static byte[] generateTestClass() {

        ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);

        cw.visit(TestOSRWithNonEmptyStack.CLASS_FILE_VERSION, ACC_PUBLIC,

                TestOSRWithNonEmptyStack.CLASS_NAME, null, "java/lang/Object",

                null);

        TestOSRWithNonEmptyStack.generateConstructor(cw);

        TestOSRWithNonEmptyStack.generateTestMethod(cw);

        cw.visitEnd();

        return cw.toByteArray();

    }

    private static void generateConstructor(ClassWriter classWriter) {

        MethodVisitor mv = classWriter.visitMethod(ACC_PUBLIC, "<init>", "()V",

                null, null);

        mv.visitCode();

        mv.visitVarInsn(ALOAD, 0);

        mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V",

                false);

        mv.visitInsn(RETURN);

        mv.visitMaxs(0, 0);

        mv.visitEnd();

    }

    private static void generateTestMethod(ClassWriter classWriter) {

        MethodVisitor mv = classWriter.visitMethod(ACC_PUBLIC,

                TestOSRWithNonEmptyStack.METHOD_NAME, "()V", null, null);

        Label osrEntryPoint = new Label();

        mv.visitCode();

        // Push 'this' into stack before OSR entry point to bail out compilation

        mv.visitVarInsn(ALOAD, 0);

        // Setup loop counter

        mv.visitInsn(ICONST_0);

        mv.visitVarInsn(ISTORE, 1);

        // Begin loop

        mv.visitLabel(osrEntryPoint);

        // Increment loop counter

        mv.visitVarInsn(ILOAD, 1);

        mv.visitInsn(ICONST_1);

        mv.visitInsn(IADD);

        // Duplicate it for loop condition check

        mv.visitInsn(DUP);

        mv.visitVarInsn(ISTORE, 1);

        // Check loop condition

        mv.visitLdcInsn(TestOSRWithNonEmptyStack.ITERATIONS);

        mv.visitJumpInsn(IF_ICMPLT, osrEntryPoint);

        // Pop 'this'.

        mv.visitInsn(POP);

        mv.visitInsn(RETURN);

        mv.visitMaxs(0, 0);

        mv.visitEnd();

    }

    private void run() {

        byte[] bytecode = TestOSRWithNonEmptyStack.generateTestClass();

        try {

            Class klass = defineClass(TestOSRWithNonEmptyStack.CLASS_NAME,

                    bytecode, 0, bytecode.length);

            Constructor ctor = klass.getConstructor();

            Method method = klass.getDeclaredMethod(

                    TestOSRWithNonEmptyStack.METHOD_NAME);

            Object testCase = ctor.newInstance();

            method.invoke(testCase);

        } catch (Exception e) {

            throw new RuntimeException(

                    "Test bug: generated class should be valid.", e);

        }

    }

    public static void main(String args[]) {

        new TestOSRWithNonEmptyStack().run();

    }

}