diff options
Diffstat (limited to 'libjava/java/lang/VMCompiler.java')
| -rw-r--r-- | libjava/java/lang/VMCompiler.java | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/libjava/java/lang/VMCompiler.java b/libjava/java/lang/VMCompiler.java new file mode 100644 index 000000000..1f600f12e --- /dev/null +++ b/libjava/java/lang/VMCompiler.java @@ -0,0 +1,369 @@ +/* VMClassLoader.java -- Reference implementation of compiler interface + Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.lang; + +import java.io.File; +import java.io.FileOutputStream; +import java.io.InputStreamReader; +import java.security.MessageDigest; +import java.security.ProtectionDomain; +import java.security.NoSuchAlgorithmException; +import java.util.WeakHashMap; +import java.util.HashSet; +import java.util.Enumeration; +import java.util.StringTokenizer; +import java.util.Vector; +import gnu.gcj.runtime.SharedLibHelper; +import gnu.gcj.runtime.PersistentByteMap; +import gnu.java.security.hash.MD5; + +/** + * This class is just a per-VM reflection of java.lang.Compiler. + * All methods are defined identically. + */ +final class VMCompiler +{ + // True if we want to use gcj-jit. + public static boolean useCompiler = true; + + // True if we're able to use gcj-jit. + public static final boolean canUseCompiler; + + // Compiler to use. + public static String gcjJitCompiler; + + // Compiler options. + public static String gcjJitCompilerOptions; + + // Temporary directory to use. + public static String gcjJitTmpdir; + + public static boolean precompiles() + { + return (canUseCompiler & useCompiler); + } + + // This maps a ClassLoader to a set of SharedLibHelper objects that + // it has used. We do things this way to ensure that a + // SharedLibHelper is collected if and only if the ClassLoader is. + private static WeakHashMap sharedHelperMap = new WeakHashMap(); + + private static Vector precompiledMapFiles; + + // We create a single MD5 engine and then clone it whenever we want + // a new one. + + // We don't use + // + // md5Digest = MessageDigest.getInstance("MD5"); + // + // here because that loads a great deal of security provider code as + // interpreted bytecode -- before we're able to use this class to + // load precompiled classes. + + private static final MD5 md5Digest + = new gnu.java.security.hash.MD5(); + + static + { + gcjJitCompiler = System.getProperty("gnu.gcj.jit.compiler"); + if (gcjJitCompiler == null) + canUseCompiler = false; + else + { + gcjJitCompilerOptions = System.getProperty("gnu.gcj.jit.options", + "-g"); + gcjJitTmpdir = System.getProperty("gnu.gcj.jit.cachedir"); + // Note that we *don't* choose java.io.tmpdir as a default -- + // that would allow easy attacks against the VM. + if (gcjJitTmpdir == null) + canUseCompiler = false; + else + canUseCompiler = true; + } + + String prop = System.getProperty ("gnu.gcj.precompiled.db.path"); + if (prop != null) + { + precompiledMapFiles = new Vector(); + // Add the + StringTokenizer st + = new StringTokenizer (prop, + System.getProperty ("path.separator", ":")); + { + while (st.hasMoreElements ()) + { + String e = st.nextToken (); + try + { + PersistentByteMap map + = new PersistentByteMap + (e, PersistentByteMap.AccessMode.READ_ONLY); + precompiledMapFiles.add(map); + } + catch (IllegalArgumentException _) + { + // Not a map file + } + catch (java.io.IOException _) + { + } + catch (java.nio.BufferUnderflowException _) + { + // Invalid map file. + } + } + } + } + } + + /** + * Don't allow new `Compiler's to be made. + */ + private VMCompiler() + { + } + + private static Class loadSharedLibrary(ClassLoader loader, + String fileName, + ProtectionDomain domain, + String className) + { + Class c = null; + SharedLibHelper helper + = SharedLibHelper.findHelper (loader, fileName, domain.getCodeSource(), + domain, false); + c = helper.findClass (className); + if (c != null) + { + HashSet hs = (HashSet) sharedHelperMap.get(loader); + if (hs == null) + { + hs = new HashSet(); + sharedHelperMap.put(loader, hs); + } + hs.add(helper); + } + return c; + } + + /** + * Compile a class given the bytes for it. Returns the Class, or + * null if compilation failed or otherwise could not be done. + */ + public static Class compileClass(ClassLoader loader, + String name, byte[] data, + int offset, int len, + ProtectionDomain domain) + { + if (precompiledMapFiles == null && !precompiles()) + return null; + + byte digest[]; + + try + { + MD5 md = (MD5) md5Digest.clone(); + md.update(data); + digest = md.digest(); + } + catch (NullPointerException _) + { + // If md5Digest==null -- but really this should never happen + // either, since the MD5 digest is in libgcj. + return null; + } + + // We use lookaside cache files to determine whether these bytes + // correspond to a class file that is part of a precompiled DSO. + if (precompiledMapFiles != null) + { + try + { + Enumeration elements = precompiledMapFiles.elements(); + while (elements.hasMoreElements()) + { + PersistentByteMap map = (PersistentByteMap)elements.nextElement(); + byte[] soName = map.get(digest); + if (soName != null) + return loadSharedLibrary(loader, + new String(soName), + domain, name); + } + } + catch (Exception _) + { + } + catch (UnknownError _) + { + // SharedLibHelper will throw UnknownError if the dlopen + // fails for some reason. We ignore it and continue on. + } + } + + if (!precompiles()) + return null; + + try + { + // FIXME: Make sure that the class represented by the + // bytes in DATA really is the class named in NAME. Make + // sure it's not "java.*". + StringBuffer hexBytes = new StringBuffer(gcjJitTmpdir); + hexBytes.append(File.separatorChar); + int digestLength = digest.length; + for (int i = 0; i < digestLength; ++i) + { + int v = digest[i] & 0xff; + if (v < 16) + hexBytes.append('0'); + hexBytes.append(Integer.toHexString(v)); + } + + // FIXME: use System.mapLibraryName? + // I'm thinking we should use that, plus a class specified + // via a property that determines lookup policy. + File soFile = new File(hexBytes + ".so"); + if (soFile.isFile()) + return loadSharedLibrary (loader, soFile.toString(), domain, + name); + + File classFile = new File(hexBytes + ".class"); + classFile.delete(); + if (classFile.createNewFile() != true) + return null; + + FileOutputStream f = new FileOutputStream (classFile); + // FIXME: race condition if bytes change... ? + f.write(data, offset, len); + + // Invoke the compiler. + StringBuffer command = new StringBuffer(gcjJitCompiler); + command.append(" "); + command.append(classFile); + command.append(" "); + command.append(gcjJitCompilerOptions); + // These options are required. + command.append(" -findirect-dispatch -fjni -shared -fPIC -o "); + command.append(soFile); + Process p = Runtime.getRuntime().exec(command.toString()); + + // Read the process' stderr into a string. + StringBuffer err = new StringBuffer(); + InputStreamReader stderr = new InputStreamReader (p.getErrorStream()); + char[] inBuf = new char[500]; + int bytesRead; + while ((bytesRead = stderr.read (inBuf)) != -1) + err.append(inBuf, 0, bytesRead); + + if (p.waitFor() != 0) + { + // FIXME: we could log err.toString() somewhere... + return null; + } + + return loadSharedLibrary(loader, soFile.toString(), domain, name); + } + catch (Exception _) + { + return null; + } + } + + /** + * Compile the class named by <code>oneClass</code>. + * + * @param oneClass the class to compile + * @return <code>false</code> if no compiler is available or + * compilation failed, <code>true</code> if compilation succeeded + * @throws NullPointerException if oneClass is null + */ + public static boolean compileClass(Class oneClass) + { + // Never succeed. + return false; + } + + /** + * Compile the classes whose name matches <code>classNames</code>. + * + * @param classNames the name of classes to compile + * @return <code>false</code> if no compiler is available or + * compilation failed, <code>true</code> if compilation succeeded + * @throws NullPointerException if classNames is null + */ + public static boolean compileClasses(String classNames) + { + // Note the incredibly lame interface. Always fail. + return false; + } + + /** + * This method examines the argument and performs an operation + * according to the compilers documentation. No specific operation + * is required. + * + * @param arg a compiler-specific argument + * @return a compiler-specific value, including null + * @throws NullPointerException if the compiler doesn't like a null arg + */ + public static Object command(Object arg) + { + // Our implementation defines this to a no-op. + return null; + } + + /** + * Calling <code>Compiler.enable()</code> will cause the compiler + * to resume operation if it was previously disabled; provided that a + * compiler even exists. + */ + public static void enable() + { + useCompiler = true; + } + + /** + * Calling <code>Compiler.disable()</code> will cause the compiler + * to be suspended; provided that a compiler even exists. + */ + public static void disable() + { + useCompiler = false; + } +} |