/*
* Copyright (c) 2015, 2016, 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 gc.testlibrary;
import jdk.test.lib.JDKToolLauncher;
import jdk.test.lib.process.OutputAnalyzer;
import sun.hotspot.WhiteBox;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
public class Helpers {
/**
* Size of a long field in bytes
*/
public static final int SIZE_OF_LONG = 8;
// In case of 128 byte padding
private static final int MAX_PADDING_SIZE = 128;
/**
* According class file format theoretical amount of fields in class is u2 which is (256 * 256 - 1).
* Some service info takes place in constant pool and we really could make a class with lesser amount of fields.
*
* Since the exact value is not so important and I would like to avoid issues that may be caused by future changes/
* different archs etc I selected (256 * 256 - 1024) for this constant.
* The test works with other values too but the smaller the number the more classes we need to generate and it takes
* more time
*/
private static final int MAXIMUM_AMOUNT_OF_FIELDS_IN_CLASS = 256 * 256 - 1024;
/**
* Detects amount of extra bytes required to allocate a byte array.
* Allocating a byte[n] array takes more then just n bytes in the heap.
* Extra bytes are required to store object reference and the length.
* This amount depends on bitness and other factors.
*
* @return byte[] memory overhead
*/
public static int detectByteArrayAllocationOverhead() {
WhiteBox whiteBox = WhiteBox.getWhiteBox();
int zeroLengthByteArraySize = (int) whiteBox.getObjectSize(new byte[0]);
// Since we do not know is there any padding in zeroLengthByteArraySize we cannot just take byte[0] size as overhead
for (int i = 1; i < MAX_PADDING_SIZE + 1; ++i) {
int realAllocationSize = (int) whiteBox.getObjectSize(new byte[i]);
if (realAllocationSize != zeroLengthByteArraySize) {
// It means we did not have any padding on previous step
return zeroLengthByteArraySize - (i - 1);
}
}
throw new Error("We cannot find byte[] memory overhead - should not reach here");
}
/**
* Compiles a java class
*
* @param className class name
* @param root root directory - where .java and .class files will be put
* @param source class source
* @throws IOException if cannot write file to specified directory
*/
public static void compileClass(String className, Path root, String source) throws IOException {
Path sourceFile = root.resolve(className + ".java");
Files.write(sourceFile, source.getBytes());
JDKToolLauncher jar = JDKToolLauncher.create("javac")
.addToolArg("-d")
.addToolArg(root.toAbsolutePath().toString())
.addToolArg("-cp")
.addToolArg(System.getProperty("java.class.path") + File.pathSeparator + root.toAbsolutePath())
.addToolArg(sourceFile.toAbsolutePath().toString());
ProcessBuilder pb = new ProcessBuilder(jar.getCommand());
OutputAnalyzer output = new OutputAnalyzer(pb.start());
output.shouldHaveExitValue(0);
}
/**
* Generates class with specified name, which extends specified class, with specified constructor and specified
* count of long fields
* Generated class will looks like this:
* public class ClassName extends SuperClass {
* ClassName() {super();}
* long f0;
* ...
* long fNNN;
* <p>
* }
*
* @param className class name
* @param superClass super class. if null - no extends clause
* @param constructor constructor. if null - no constructor
* @param fieldCount count of long fields
* @return class text
*/
public static String generate(String className, String superClass, String constructor, long fieldCount) {
return new StringBuilder()
.append(String.format("public class %s%s {\n", className, superClass == null ? ""
: " extends " + superClass))
.append(constructor == null ? "" : constructor)
.append(fieldsGenerator(fieldCount))
.append("}\n")
.toString();
}
/**
* Generates specified amount of long fields
* Result string will looks like this:
* <p>
* long f0;
* ...
* long fNNN;
*
* @param fieldCount count of long fields
* @return generated fields
*/
private static String fieldsGenerator(long fieldCount) {
StringBuilder fieldsBuilder = new StringBuilder();
for (int i = 0; i < fieldCount; ++i) {
fieldsBuilder.append(String.format("long f%d;\n", i));
}
return fieldsBuilder.toString();
}
/**
* Changes string from enum notation to class notation - i.e. "VERY_SMALL_CAT" to "VerySmallCat"
*
* @param enumName string in enum notation
* @return string in class notation
*/
public static String enumNameToClassName(String enumName) {
if (enumName == null) {
return null;
}
StringBuilder builder = new StringBuilder();
boolean toLowerCase = false;
for (int i = 0; i < enumName.length(); ++i) {
if (enumName.charAt(i) == '_') {
toLowerCase = false;
} else {
builder.append(toLowerCase ? String.valueOf(enumName.charAt(i)).toLowerCase() :
String.valueOf(enumName.charAt(i)));
toLowerCase = true;
}
}
return builder.toString();
}
/**
* Generates and compiles class with instance of specified size and load it in specified class loader
* Generated class will looks like this:
* public class ClassName extends SuperClass {
* long f0;
* ...
* long fNNN;
* <p>
* }
*
* @param classLoader class loader
* @param className generated class name
* @param instanceSize size of generated class' instance. Size should be aligned by 8 bytes
* @param workDir working dir where generated classes are put and compiled
* @param prefix prefix for service classes (ones we use to create chain of inheritance).
* The names will be prefix_1, prefix_2,.., prefix_n
* @return Class object of generated and compiled class loaded in specified class loader
* @throws IOException
* @throws ClassNotFoundException
*/
public static Class<?> generateCompileAndLoad(ClassLoader classLoader, String className, long instanceSize,
Path workDir, String prefix)
throws IOException, ClassNotFoundException {
generateByTemplateAndCompile(className, null, "public class ${ClassName} extends ${BaseClass} {\n${Fields}}\n",
"", instanceSize, workDir, prefix);
return classLoader.loadClass(className);
}
/**
* Creates a class which instances will be approximately of the requested size.
* This method produces a java source from a class template by substituting values instead of parameters.
* Then the obtained source is compiled.
* Generated class will looks like this:
* classTemplate
* constructorTemplate
* long f0;
* ...
* long fNNN;
* <p>
* }
*
* @param className generated class name
* @param baseClass base class
* @param classTemplate class template - the first part of class. ${ClassName} and ${BaseClass} will be replaced
* with values from className and baseClass,one entry of ${Fields} will be replaced with
* generated long fields. Class template should look like this:
* imports;
* public class ${ClassName} extends ${BaseClass} {
* public ${ClassName} { some code here;}
* some methods
* ${Fields}
*
* }
* @param constructorTemplate constructor template, ${ClassName} would be replaced on actual class name
* @param instanceSize size of generated class' instance. Size should be aligned by 8 bytes
* @param workDir working dir where generated classes are put and compiled
* @param prefix prefix for service classes (ones we use to create chain of inheritance).
* The names will be prefix_1, prefix_2,.., prefix_n
* @return Class object of generated and compiled class loaded in specified class loader
* @throws IOException if cannot write or read to workDir
*/
public static void generateByTemplateAndCompile(String className, String baseClass, String classTemplate,
String constructorTemplate, long instanceSize, Path workDir,
String prefix) throws IOException {
if (instanceSize % SIZE_OF_LONG != 0L) {
throw new Error(String.format("Test bug: only sizes aligned by %d bytes are supported and %d was specified",
SIZE_OF_LONG, instanceSize));
}
int instanceSizeWithoutObjectHeaderInWords =
(int) (instanceSize - WhiteBox.getWhiteBox().getObjectSize(new Object())) / SIZE_OF_LONG;
if (instanceSizeWithoutObjectHeaderInWords <= 0) {
throw new Error(String.format("Test bug: specified instance size is too small - %d."
+ " Cannot generate any classes", instanceSize));
}
int sizeOfLastFile = instanceSizeWithoutObjectHeaderInWords % MAXIMUM_AMOUNT_OF_FIELDS_IN_CLASS;
int generatedClassesCount = instanceSizeWithoutObjectHeaderInWords / MAXIMUM_AMOUNT_OF_FIELDS_IN_CLASS;
// Do all the classes have the maximum number of fields?
int fieldsInLastClassCount;
if (sizeOfLastFile == 0) {
fieldsInLastClassCount = MAXIMUM_AMOUNT_OF_FIELDS_IN_CLASS;
} else {
generatedClassesCount++;
fieldsInLastClassCount = sizeOfLastFile;
}
// first (generatedClassesCount - 1) classes are just fillers - just long fields and constructor
for (int i = 0; i < generatedClassesCount - 1; i++) {
String clsName = prefix + i;
Helpers.compileClass(clsName, workDir,
Helpers.generate(
clsName,
// first generated class extends base class
(i == 0 ? baseClass : prefix + (i - 1)),
constructorTemplate.replace("${ClassName}", clsName),
MAXIMUM_AMOUNT_OF_FIELDS_IN_CLASS));
}
// generating last class - the one with specified className
Helpers.compileClass(className, workDir,
classTemplate.replaceAll("\\$\\{ClassName\\}", className)
// if no fillers were generated (generatedClassesCount == 1)
// the last class should extends baseClass
// otherwise it should extend last generated filler class which name is
// prefix + (generatedClassesCount - 2)
// generatedClassesCount is always not smaller than 1
.replace("${BaseClass}",
generatedClassesCount == 1 ? baseClass :
prefix + (generatedClassesCount - 2))
.replace("${Fields}", fieldsGenerator(fieldsInLastClassCount))
);
}
/**
* Waits until Concurent Mark Cycle finishes
*
* @param wb Whitebox instance
* @param sleepTime sleep time
*/
public static void waitTillCMCFinished(WhiteBox wb, int sleepTime) {
while (wb.g1InConcurrentMark()) {
if (sleepTime > -1) {
try {
Thread.sleep(sleepTime);
} catch (InterruptedException e) {
System.out.println("Got InterruptedException while waiting for ConcMarkCycle to finish");
Thread.currentThread().interrupt();
break;
}
}
}
}
}