Mercurial > jdk8-mips64-public > langtools / file revision

 /*

  * Copyright 1999-2008 Sun Microsystems, Inc.  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.  Sun designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Sun in the LICENSE file that accompanied this code.

  *

  * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package com.sun.tools.javac.main;

 import java.io.*;

 import java.util.HashSet;

 import java.util.LinkedHashSet;

 import java.util.LinkedHashMap;

 import java.util.Map;

 import java.util.MissingResourceException;

 import java.util.ResourceBundle;

 import java.util.Set;

 import java.util.logging.Handler;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.tools.JavaFileManager;

 import javax.tools.JavaFileObject;

 import javax.tools.DiagnosticListener;

 import com.sun.tools.javac.file.JavacFileManager;

 import com.sun.source.util.TaskEvent;

 import com.sun.source.util.TaskListener;

 import com.sun.tools.javac.util.*;

 import com.sun.tools.javac.code.*;

 import com.sun.tools.javac.tree.*;

 import com.sun.tools.javac.parser.*;

 import com.sun.tools.javac.comp.*;

 import com.sun.tools.javac.jvm.*;

 import com.sun.tools.javac.code.Symbol.*;

 import com.sun.tools.javac.tree.JCTree.*;

 import com.sun.tools.javac.processing.*;

 import javax.annotation.processing.Processor;

 import static javax.tools.StandardLocation.CLASS_OUTPUT;

 import static com.sun.tools.javac.util.ListBuffer.lb;

 // TEMP, until we have a more efficient way to save doc comment info

 import com.sun.tools.javac.parser.DocCommentScanner;

 import java.util.HashMap;

 import java.util.Queue;

 import javax.lang.model.SourceVersion;

 /** This class could be the main entry point for GJC when GJC is used as a

  *  component in a larger software system. It provides operations to

  *  construct a new compiler, and to run a new compiler on a set of source

  *  files.

  *

  *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If

  *  you write code that depends on this, you do so at your own risk.

  *  This code and its internal interfaces are subject to change or

  *  deletion without notice.</b>

  */

 public class JavaCompiler implements ClassReader.SourceCompleter {

     /** The context key for the compiler. */

     protected static final Context.Key<JavaCompiler> compilerKey =

         new Context.Key<JavaCompiler>();

     /** Get the JavaCompiler instance for this context. */

     public static JavaCompiler instance(Context context) {

         JavaCompiler instance = context.get(compilerKey);

         if (instance == null)

             instance = new JavaCompiler(context);

         return instance;

     }

     /** The current version number as a string.

      */

     public static String version() {

         return version("release");  // mm.nn.oo[-milestone]

     }

     /** The current full version number as a string.

      */

     public static String fullVersion() {

         return version("full"); // mm.mm.oo[-milestone]-build

     }

     private static final String versionRBName = "com.sun.tools.javac.resources.version";

     private static ResourceBundle versionRB;

     private static String version(String key) {

         if (versionRB == null) {

             try {

                 versionRB = ResourceBundle.getBundle(versionRBName);

             } catch (MissingResourceException e) {

                 return Log.getLocalizedString("version.resource.missing", System.getProperty("java.version"));

             }

         }

         try {

             return versionRB.getString(key);

         }

         catch (MissingResourceException e) {

             return Log.getLocalizedString("version.unknown", System.getProperty("java.version"));

         }

     }

     /**

      * Control how the compiler's latter phases (attr, flow, desugar, generate)

      * are connected. Each individual file is processed by each phase in turn,

      * but with different compile policies, you can control the order in which

      * each class is processed through its next phase.

      *

      * <p>Generally speaking, the compiler will "fail fast" in the face of

      * errors, although not aggressively so. flow, desugar, etc become no-ops

      * once any errors have occurred. No attempt is currently made to determine

      * if it might be safe to process a class through its next phase because

      * it does not depend on any unrelated errors that might have occurred.

      */

     protected static enum CompilePolicy {

         /**

          * Just attribute the parse trees.

          */

         ATTR_ONLY,

         /**

          * Just attribute and do flow analysis on the parse trees.

          * This should catch most user errors.

          */

         CHECK_ONLY,

         /**

          * Attribute everything, then do flow analysis for everything,

          * then desugar everything, and only then generate output.

          * This means no output will be generated if there are any

          * errors in any classes.

          */

         SIMPLE,

         /**

          * Groups the classes for each source file together, then process

          * each group in a manner equivalent to the {@code SIMPLE} policy.

          * This means no output will be generated if there are any

          * errors in any of the classes in a source file.

          */

         BY_FILE,

         /**

          * Completely process each entry on the todo list in turn.

          * -- this is the same for 1.5.

          * Means output might be generated for some classes in a compilation unit

          * and not others.

          */

         BY_TODO;

         static CompilePolicy decode(String option) {

             if (option == null)

                 return DEFAULT_COMPILE_POLICY;

             else if (option.equals("attr"))

                 return ATTR_ONLY;

             else if (option.equals("check"))

                 return CHECK_ONLY;

             else if (option.equals("simple"))

                 return SIMPLE;

             else if (option.equals("byfile"))

                 return BY_FILE;

             else if (option.equals("bytodo"))

                 return BY_TODO;

             else

                 return DEFAULT_COMPILE_POLICY;

         }

     }

     private static CompilePolicy DEFAULT_COMPILE_POLICY = CompilePolicy.BY_TODO;

     protected static enum ImplicitSourcePolicy {

         /** Don't generate or process implicitly read source files. */

         NONE,

         /** Generate classes for implicitly read source files. */

         CLASS,

         /** Like CLASS, but generate warnings if annotation processing occurs */

         UNSET;

         static ImplicitSourcePolicy decode(String option) {

             if (option == null)

                 return UNSET;

             else if (option.equals("none"))

                 return NONE;

             else if (option.equals("class"))

                 return CLASS;

             else

                 return UNSET;

         }

     }

     /** The log to be used for error reporting.

      */

     public Log log;

     /** Factory for creating diagnostic objects

      */

     JCDiagnostic.Factory diagFactory;

     /** The tree factory module.

      */

     protected TreeMaker make;

     /** The class reader.

      */

     protected ClassReader reader;

     /** The class writer.

      */

     protected ClassWriter writer;

     /** The module for the symbol table entry phases.

      */

     protected Enter enter;

     /** The symbol table.

      */

     protected Symtab syms;

     /** The language version.

      */

     protected Source source;

     /** The module for code generation.

      */

     protected Gen gen;

     /** The name table.

      */

     protected Names names;

     /** The attributor.

      */

     protected Attr attr;

     /** The attributor.

      */

     protected Check chk;

     /** The flow analyzer.

      */

     protected Flow flow;

     /** The type eraser.

      */

     protected TransTypes transTypes;

     /** The syntactic sugar desweetener.

      */

     protected Lower lower;

     /** The annotation annotator.

      */

     protected Annotate annotate;

     /** Force a completion failure on this name

      */

     protected final Name completionFailureName;

     /** Type utilities.

      */

     protected Types types;

     /** Access to file objects.

      */

     protected JavaFileManager fileManager;

     /** Factory for parsers.

      */

     protected ParserFactory parserFactory;

     /** Optional listener for progress events

      */

     protected TaskListener taskListener;

     /**

      * Annotation processing may require and provide a new instance

      * of the compiler to be used for the analyze and generate phases.

      */

     protected JavaCompiler delegateCompiler;

     /**

      * Flag set if any annotation processing occurred.

      **/

     protected boolean annotationProcessingOccurred;

     /**

      * Flag set if any implicit source files read.

      **/

     protected boolean implicitSourceFilesRead;

     protected Context context;

     /** Construct a new compiler using a shared context.

      */

     public JavaCompiler(final Context context) {

         this.context = context;

         context.put(compilerKey, this);

         // if fileManager not already set, register the JavacFileManager to be used

         if (context.get(JavaFileManager.class) == null)

             JavacFileManager.preRegister(context);

         names = Names.instance(context);

         log = Log.instance(context);

         diagFactory = JCDiagnostic.Factory.instance(context);

         reader = ClassReader.instance(context);

         make = TreeMaker.instance(context);

         writer = ClassWriter.instance(context);

         enter = Enter.instance(context);

         todo = Todo.instance(context);

         fileManager = context.get(JavaFileManager.class);

         parserFactory = ParserFactory.instance(context);

         try {

             // catch completion problems with predefineds

             syms = Symtab.instance(context);

         } catch (CompletionFailure ex) {

             // inlined Check.completionError as it is not initialized yet

             log.error("cant.access", ex.sym, ex.getDetailValue());

             if (ex instanceof ClassReader.BadClassFile)

                 throw new Abort();

         }

         source = Source.instance(context);

         attr = Attr.instance(context);

         chk = Check.instance(context);

         gen = Gen.instance(context);

         flow = Flow.instance(context);

         transTypes = TransTypes.instance(context);

         lower = Lower.instance(context);

         annotate = Annotate.instance(context);

         types = Types.instance(context);

         taskListener = context.get(TaskListener.class);

         reader.sourceCompleter = this;

         Options options = Options.instance(context);

         verbose       = options.get("-verbose")       != null;

         sourceOutput  = options.get("-printsource")   != null; // used to be -s

         stubOutput    = options.get("-stubs")         != null;

         relax         = options.get("-relax")         != null;

         printFlat     = options.get("-printflat")     != null;

         attrParseOnly = options.get("-attrparseonly") != null;

         encoding      = options.get("-encoding");

         lineDebugInfo = options.get("-g:")            == null ||

                         options.get("-g:lines")       != null;

         genEndPos     = options.get("-Xjcov")         != null ||

                         context.get(DiagnosticListener.class) != null;

         devVerbose    = options.get("dev") != null;

         processPcks   = options.get("process.packages") != null;

         verboseCompilePolicy = options.get("verboseCompilePolicy") != null;

         if (attrParseOnly)

             compilePolicy = CompilePolicy.ATTR_ONLY;

         else

             compilePolicy = CompilePolicy.decode(options.get("compilePolicy"));

         implicitSourcePolicy = ImplicitSourcePolicy.decode(options.get("-implicit"));

         completionFailureName =

             (options.get("failcomplete") != null)

             ? names.fromString(options.get("failcomplete"))

             : null;

     }

     /* Switches:

      */

     /** Verbose output.

      */

     public boolean verbose;

     /** Emit plain Java source files rather than class files.

      */

     public boolean sourceOutput;

     /** Emit stub source files rather than class files.

      */

     public boolean stubOutput;

     /** Generate attributed parse tree only.

      */

     public boolean attrParseOnly;

     /** Switch: relax some constraints for producing the jsr14 prototype.

      */

     boolean relax;

     /** Debug switch: Emit Java sources after inner class flattening.

      */

     public boolean printFlat;

     /** The encoding to be used for source input.

      */

     public String encoding;

     /** Generate code with the LineNumberTable attribute for debugging

      */

     public boolean lineDebugInfo;

     /** Switch: should we store the ending positions?

      */

     public boolean genEndPos;

     /** Switch: should we debug ignored exceptions

      */

     protected boolean devVerbose;

     /** Switch: should we (annotation) process packages as well

      */

     protected boolean processPcks;

     /** Switch: is annotation processing requested explitly via

      * CompilationTask.setProcessors?

      */

     protected boolean explicitAnnotationProcessingRequested = false;

     /**

      * The policy for the order in which to perform the compilation

      */

     protected CompilePolicy compilePolicy;

     /**

      * The policy for what to do with implicitly read source files

      */

     protected ImplicitSourcePolicy implicitSourcePolicy;

     /**

      * Report activity related to compilePolicy

      */

     public boolean verboseCompilePolicy;

     /** A queue of all as yet unattributed classes.

      */

     public Todo todo;

     protected enum CompileState {

         TODO(0),

         ATTR(1),

         FLOW(2);

         CompileState(int value) {

             this.value = value;

         }

         boolean isDone(CompileState other) {

             return value >= other.value;

         }

         private int value;

     };

     protected class CompileStates extends HashMap<Env<AttrContext>,CompileState> {

         private static final long serialVersionUID = 1812267524140424433L;

         boolean isDone(Env<AttrContext> env, CompileState cs) {

             CompileState ecs = get(env);

             return ecs != null && ecs.isDone(cs);

         }

     }

     private CompileStates compileStates = new CompileStates();

     /** The set of currently compiled inputfiles, needed to ensure

      *  we don't accidentally overwrite an input file when -s is set.

      *  initialized by `compile'.

      */

     protected Set<JavaFileObject> inputFiles = new HashSet<JavaFileObject>();

     /** The number of errors reported so far.

      */

     public int errorCount() {

         if (delegateCompiler != null && delegateCompiler != this)

             return delegateCompiler.errorCount();

         else

             return log.nerrors;

     }

     protected final <T> Queue<T> stopIfError(Queue<T> queue) {

         if (errorCount() == 0)

             return queue;

         else

             return ListBuffer.lb();

     }

     protected final <T> List<T> stopIfError(List<T> list) {

         if (errorCount() == 0)

             return list;

         else

             return List.nil();

     }

     /** The number of warnings reported so far.

      */

     public int warningCount() {

         if (delegateCompiler != null && delegateCompiler != this)

             return delegateCompiler.warningCount();

         else

             return log.nwarnings;

     }

     /** Whether or not any parse errors have occurred.

      */

     public boolean parseErrors() {

         return parseErrors;

     }

     /** Try to open input stream with given name.

      *  Report an error if this fails.

      *  @param filename   The file name of the input stream to be opened.

      */

     public CharSequence readSource(JavaFileObject filename) {

         try {

             inputFiles.add(filename);

             return filename.getCharContent(false);

         } catch (IOException e) {

             log.error("error.reading.file", filename, e.getLocalizedMessage());

             return null;

         }

     }

     /** Parse contents of input stream.

      *  @param filename     The name of the file from which input stream comes.

      *  @param input        The input stream to be parsed.

      */

     protected JCCompilationUnit parse(JavaFileObject filename, CharSequence content) {

         long msec = now();

         JCCompilationUnit tree = make.TopLevel(List.<JCTree.JCAnnotation>nil(),

                                       null, List.<JCTree>nil());

         if (content != null) {

             if (verbose) {

                 printVerbose("parsing.started", filename);

             }

             if (taskListener != null) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.PARSE, filename);

                 taskListener.started(e);

             }

             int initialErrorCount = log.nerrors;

             Parser parser = parserFactory.newParser(content, keepComments(), genEndPos, lineDebugInfo);

             tree = parser.parseCompilationUnit();

             parseErrors |= (log.nerrors > initialErrorCount);

             if (verbose) {

                 printVerbose("parsing.done", Long.toString(elapsed(msec)));

             }

         }

         tree.sourcefile = filename;

         if (content != null && taskListener != null) {

             TaskEvent e = new TaskEvent(TaskEvent.Kind.PARSE, tree);

             taskListener.finished(e);

         }

         return tree;

     }

     // where

         public boolean keepComments = false;

         protected boolean keepComments() {

             return keepComments || sourceOutput || stubOutput;

         }

     /** Parse contents of file.

      *  @param filename     The name of the file to be parsed.

      */

     @Deprecated

     public JCTree.JCCompilationUnit parse(String filename) throws IOException {

         JavacFileManager fm = (JavacFileManager)fileManager;

         return parse(fm.getJavaFileObjectsFromStrings(List.of(filename)).iterator().next());

     }

     /** Parse contents of file.

      *  @param filename     The name of the file to be parsed.

      */

     public JCTree.JCCompilationUnit parse(JavaFileObject filename) {

         JavaFileObject prev = log.useSource(filename);

         try {

             JCTree.JCCompilationUnit t = parse(filename, readSource(filename));

             if (t.endPositions != null)

                 log.setEndPosTable(filename, t.endPositions);

             return t;

         } finally {

             log.useSource(prev);

         }

     }

     /** Resolve an identifier.

      * @param name      The identifier to resolve

      */

     public Symbol resolveIdent(String name) {

         if (name.equals(""))

             return syms.errSymbol;

         JavaFileObject prev = log.useSource(null);

         try {

             JCExpression tree = null;

             for (String s : name.split("\\.", -1)) {

                 if (!SourceVersion.isIdentifier(s)) // TODO: check for keywords

                     return syms.errSymbol;

                 tree = (tree == null) ? make.Ident(names.fromString(s))

                                       : make.Select(tree, names.fromString(s));

             }

             JCCompilationUnit toplevel =

                 make.TopLevel(List.<JCTree.JCAnnotation>nil(), null, List.<JCTree>nil());

             toplevel.packge = syms.unnamedPackage;

             return attr.attribIdent(tree, toplevel);

         } finally {

             log.useSource(prev);

         }

     }

     /** Emit plain Java source for a class.

      *  @param env    The attribution environment of the outermost class

      *                containing this class.

      *  @param cdef   The class definition to be printed.

      */

     JavaFileObject printSource(Env<AttrContext> env, JCClassDecl cdef) throws IOException {

         JavaFileObject outFile

             = fileManager.getJavaFileForOutput(CLASS_OUTPUT,

                                                cdef.sym.flatname.toString(),

                                                JavaFileObject.Kind.SOURCE,

                                                null);

         if (inputFiles.contains(outFile)) {

             log.error(cdef.pos(), "source.cant.overwrite.input.file", outFile);

             return null;

         } else {

             BufferedWriter out = new BufferedWriter(outFile.openWriter());

             try {

                 new Pretty(out, true).printUnit(env.toplevel, cdef);

                 if (verbose)

                     printVerbose("wrote.file", outFile);

             } finally {

                 out.close();

             }

             return outFile;

         }

     }

     /** Generate code and emit a class file for a given class

      *  @param env    The attribution environment of the outermost class

      *                containing this class.

      *  @param cdef   The class definition from which code is generated.

      */

     JavaFileObject genCode(Env<AttrContext> env, JCClassDecl cdef) throws IOException {

         try {

             if (gen.genClass(env, cdef))

                 return writer.writeClass(cdef.sym);

         } catch (ClassWriter.PoolOverflow ex) {

             log.error(cdef.pos(), "limit.pool");

         } catch (ClassWriter.StringOverflow ex) {

             log.error(cdef.pos(), "limit.string.overflow",

                       ex.value.substring(0, 20));

         } catch (CompletionFailure ex) {

             chk.completionError(cdef.pos(), ex);

         }

         return null;

     }

     /** Complete compiling a source file that has been accessed

      *  by the class file reader.

      *  @param c          The class the source file of which needs to be compiled.

      *  @param filename   The name of the source file.

      *  @param f          An input stream that reads the source file.

      */

     public void complete(ClassSymbol c) throws CompletionFailure {

 //      System.err.println("completing " + c);//DEBUG

         if (completionFailureName == c.fullname) {

             throw new CompletionFailure(c, "user-selected completion failure by class name");

         }

         JCCompilationUnit tree;

         JavaFileObject filename = c.classfile;

         JavaFileObject prev = log.useSource(filename);

         try {

             tree = parse(filename, filename.getCharContent(false));

         } catch (IOException e) {

             log.error("error.reading.file", filename, e);

             tree = make.TopLevel(List.<JCTree.JCAnnotation>nil(), null, List.<JCTree>nil());

         } finally {

             log.useSource(prev);

         }

         if (taskListener != null) {

             TaskEvent e = new TaskEvent(TaskEvent.Kind.ENTER, tree);

             taskListener.started(e);

         }

         enter.complete(List.of(tree), c);

         if (taskListener != null) {

             TaskEvent e = new TaskEvent(TaskEvent.Kind.ENTER, tree);

             taskListener.finished(e);

         }

         if (enter.getEnv(c) == null) {

             boolean isPkgInfo =

                 tree.sourcefile.isNameCompatible("package-info",

                                                  JavaFileObject.Kind.SOURCE);

             if (isPkgInfo) {

                 if (enter.getEnv(tree.packge) == null) {

                     JCDiagnostic diag =

                         diagFactory.fragment("file.does.not.contain.package",

                                                  c.location());

                     throw reader.new BadClassFile(c, filename, diag);

                 }

             } else {

                 JCDiagnostic diag =

                         diagFactory.fragment("file.doesnt.contain.class",

                                             c.getQualifiedName());

                 throw reader.new BadClassFile(c, filename, diag);

             }

         }

         implicitSourceFilesRead = true;

     }

     /** Track when the JavaCompiler has been used to compile something. */

     private boolean hasBeenUsed = false;

     private long start_msec = 0;

     public long elapsed_msec = 0;

     /** Track whether any errors occurred while parsing source text. */

     private boolean parseErrors = false;

     public void compile(List<JavaFileObject> sourceFileObject)

         throws Throwable {

         compile(sourceFileObject, List.<String>nil(), null);

     }

     /**

      * Main method: compile a list of files, return all compiled classes

      *

      * @param sourceFileObjects file objects to be compiled

      * @param classnames class names to process for annotations

      * @param processors user provided annotation processors to bypass

      * discovery, {@code null} means that no processors were provided

      */

     public void compile(List<JavaFileObject> sourceFileObjects,

                         List<String> classnames,

                         Iterable<? extends Processor> processors)

         throws IOException // TODO: temp, from JavacProcessingEnvironment

     {

         if (processors != null && processors.iterator().hasNext())

             explicitAnnotationProcessingRequested = true;

         // as a JavaCompiler can only be used once, throw an exception if

         // it has been used before.

         if (hasBeenUsed)

             throw new AssertionError("attempt to reuse JavaCompiler");

         hasBeenUsed = true;

         start_msec = now();

         try {

             initProcessAnnotations(processors);

             // These method calls must be chained to avoid memory leaks

             delegateCompiler = processAnnotations(enterTrees(stopIfError(parseFiles(sourceFileObjects))),

                                                   classnames);

             delegateCompiler.compile2();

             delegateCompiler.close();

             elapsed_msec = delegateCompiler.elapsed_msec;

         } catch (Abort ex) {

             if (devVerbose)

                 ex.printStackTrace();

         }

     }

     /**

      * The phases following annotation processing: attribution,

      * desugar, and finally code generation.

      */

     private void compile2() {

         try {

             switch (compilePolicy) {

             case ATTR_ONLY:

                 attribute(todo);

                 break;

             case CHECK_ONLY:

                 flow(attribute(todo));

                 break;

             case SIMPLE:

                 generate(desugar(flow(attribute(todo))));

                 break;

             case BY_FILE: {

                     Queue<Queue<Env<AttrContext>>> q = todo.groupByFile();

                     while (!q.isEmpty() && errorCount() == 0) {

                         generate(desugar(flow(attribute(q.remove()))));

                     }

                 }

                 break;

             case BY_TODO:

                 while (!todo.isEmpty())

                     generate(desugar(flow(attribute(todo.remove()))));

                 break;

             default:

                 assert false: "unknown compile policy";

             }

         } catch (Abort ex) {

             if (devVerbose)

                 ex.printStackTrace();

         }

         if (verbose) {

             elapsed_msec = elapsed(start_msec);

             printVerbose("total", Long.toString(elapsed_msec));

         }

         reportDeferredDiagnostics();

         if (!log.hasDiagnosticListener()) {

             printCount("error", errorCount());

             printCount("warn", warningCount());

         }

     }

     private List<JCClassDecl> rootClasses;

     /**

      * Parses a list of files.

      */

    public List<JCCompilationUnit> parseFiles(List<JavaFileObject> fileObjects) throws IOException {

        if (errorCount() > 0)

            return List.nil();

         //parse all files

         ListBuffer<JCCompilationUnit> trees = lb();

         for (JavaFileObject fileObject : fileObjects)

             trees.append(parse(fileObject));

         return trees.toList();

     }

     /**

      * Enter the symbols found in a list of parse trees.

      * As a side-effect, this puts elements on the "todo" list.

      * Also stores a list of all top level classes in rootClasses.

      */

     public List<JCCompilationUnit> enterTrees(List<JCCompilationUnit> roots) {

         //enter symbols for all files

         if (taskListener != null) {

             for (JCCompilationUnit unit: roots) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.ENTER, unit);

                 taskListener.started(e);

             }

         }

         enter.main(roots);

         if (taskListener != null) {

             for (JCCompilationUnit unit: roots) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.ENTER, unit);

                 taskListener.finished(e);

             }

         }

         //If generating source, remember the classes declared in

         //the original compilation units listed on the command line.

         if (sourceOutput || stubOutput) {

             ListBuffer<JCClassDecl> cdefs = lb();

             for (JCCompilationUnit unit : roots) {

                 for (List<JCTree> defs = unit.defs;

                      defs.nonEmpty();

                      defs = defs.tail) {

                     if (defs.head instanceof JCClassDecl)

                         cdefs.append((JCClassDecl)defs.head);

                 }

             }

             rootClasses = cdefs.toList();

         }

         return roots;

     }

     /**

      * Set to true to enable skeleton annotation processing code.

      * Currently, we assume this variable will be replaced more

      * advanced logic to figure out if annotation processing is

      * needed.

      */

     boolean processAnnotations = false;

     /**

      * Object to handle annotation processing.

      */

     JavacProcessingEnvironment procEnvImpl = null;

     /**

      * Check if we should process annotations.

      * If so, and if no scanner is yet registered, then set up the DocCommentScanner

      * to catch doc comments, and set keepComments so the parser records them in

      * the compilation unit.

      *

      * @param processors user provided annotation processors to bypass

      * discovery, {@code null} means that no processors were provided

      */

     public void initProcessAnnotations(Iterable<? extends Processor> processors) {

         // Process annotations if processing is not disabled and there

         // is at least one Processor available.

         Options options = Options.instance(context);

         if (options.get("-proc:none") != null) {

             processAnnotations = false;

         } else if (procEnvImpl == null) {

             procEnvImpl = new JavacProcessingEnvironment(context, processors);

             processAnnotations = procEnvImpl.atLeastOneProcessor();

             if (processAnnotations) {

                 if (context.get(Scanner.Factory.scannerFactoryKey) == null)

                     DocCommentScanner.Factory.preRegister(context);

                 options.put("save-parameter-names", "save-parameter-names");

                 reader.saveParameterNames = true;

                 keepComments = true;

                 if (taskListener != null)

                     taskListener.started(new TaskEvent(TaskEvent.Kind.ANNOTATION_PROCESSING));

             } else { // free resources

                 procEnvImpl.close();

             }

         }

     }

     // TODO: called by JavacTaskImpl

     public JavaCompiler processAnnotations(List<JCCompilationUnit> roots) throws IOException {

         return processAnnotations(roots, List.<String>nil());

     }

     /**

      * Process any anotations found in the specifed compilation units.

      * @param roots a list of compilation units

      * @return an instance of the compiler in which to complete the compilation

      */

     public JavaCompiler processAnnotations(List<JCCompilationUnit> roots,

                                            List<String> classnames)

         throws IOException  { // TODO: see TEMP note in JavacProcessingEnvironment

         if (errorCount() != 0) {

             // Errors were encountered.  If todo is empty, then the

             // encountered errors were parse errors.  Otherwise, the

             // errors were found during the enter phase which should

             // be ignored when processing annotations.

             if (todo.isEmpty())

                 return this;

         }

         // ASSERT: processAnnotations and procEnvImpl should have been set up by

         // by initProcessAnnotations

         // NOTE: The !classnames.isEmpty() checks should be refactored to Main.

         if (!processAnnotations) {

             // If there are no annotation processors present, and

             // annotation processing is to occur with compilation,

             // emit a warning.

             Options options = Options.instance(context);

             if (options.get("-proc:only") != null) {

                 log.warning("proc.proc-only.requested.no.procs");

                 todo.clear();

             }

             // If not processing annotations, classnames must be empty

             if (!classnames.isEmpty()) {

                 log.error("proc.no.explicit.annotation.processing.requested",

                           classnames);

             }

             return this; // continue regular compilation

         }

         try {

             List<ClassSymbol> classSymbols = List.nil();

             List<PackageSymbol> pckSymbols = List.nil();

             if (!classnames.isEmpty()) {

                  // Check for explicit request for annotation

                  // processing

                 if (!explicitAnnotationProcessingRequested()) {

                     log.error("proc.no.explicit.annotation.processing.requested",

                               classnames);

                     return this; // TODO: Will this halt compilation?

                 } else {

                     boolean errors = false;

                     for (String nameStr : classnames) {

                         Symbol sym = resolveIdent(nameStr);

                         if (sym == null || (sym.kind == Kinds.PCK && !processPcks)) {

                             log.error("proc.cant.find.class", nameStr);

                             errors = true;

                             continue;

                         }

                         try {

                             if (sym.kind == Kinds.PCK)

                                 sym.complete();

                             if (sym.exists()) {

                                 Name name = names.fromString(nameStr);

                                 if (sym.kind == Kinds.PCK)

                                     pckSymbols = pckSymbols.prepend((PackageSymbol)sym);

                                 else

                                     classSymbols = classSymbols.prepend((ClassSymbol)sym);

                                 continue;

                             }

                             assert sym.kind == Kinds.PCK;

                             log.warning("proc.package.does.not.exist", nameStr);

                             pckSymbols = pckSymbols.prepend((PackageSymbol)sym);

                         } catch (CompletionFailure e) {

                             log.error("proc.cant.find.class", nameStr);

                             errors = true;

                             continue;

                         }

                     }

                     if (errors)

                         return this;

                 }

             }

             JavaCompiler c = procEnvImpl.doProcessing(context, roots, classSymbols, pckSymbols);

             if (c != this)

                 annotationProcessingOccurred = c.annotationProcessingOccurred = true;

             return c;

         } catch (CompletionFailure ex) {

             log.error("cant.access", ex.sym, ex.getDetailValue());

             return this;

         }

     }

     boolean explicitAnnotationProcessingRequested() {

         Options options = Options.instance(context);

         return

             explicitAnnotationProcessingRequested ||

             options.get("-processor") != null ||

             options.get("-processorpath") != null ||

             options.get("-proc:only") != null ||

             options.get("-Xprint") != null;

     }

     /**

      * Attribute a list of parse trees, such as found on the "todo" list.

      * Note that attributing classes may cause additional files to be

      * parsed and entered via the SourceCompleter.

      * Attribution of the entries in the list does not stop if any errors occur.

      * @returns a list of environments for attributd classes.

      */

     public Queue<Env<AttrContext>> attribute(Queue<Env<AttrContext>> envs) {

         ListBuffer<Env<AttrContext>> results = lb();

         while (!envs.isEmpty())

             results.append(attribute(envs.remove()));

         return results;

     }

     /**

      * Attribute a parse tree.

      * @returns the attributed parse tree

      */

     public Env<AttrContext> attribute(Env<AttrContext> env) {

         if (compileStates.isDone(env, CompileState.ATTR))

             return env;

         if (verboseCompilePolicy)

             log.printLines(log.noticeWriter, "[attribute " + env.enclClass.sym + "]");

         if (verbose)

             printVerbose("checking.attribution", env.enclClass.sym);

         if (taskListener != null) {

             TaskEvent e = new TaskEvent(TaskEvent.Kind.ANALYZE, env.toplevel, env.enclClass.sym);

             taskListener.started(e);

         }

         JavaFileObject prev = log.useSource(

                                   env.enclClass.sym.sourcefile != null ?

                                   env.enclClass.sym.sourcefile :

                                   env.toplevel.sourcefile);

         try {

             attr.attribClass(env.tree.pos(), env.enclClass.sym);

             compileStates.put(env, CompileState.ATTR);

         }

         finally {

             log.useSource(prev);

         }

         return env;

     }

     /**

      * Perform dataflow checks on attributed parse trees.

      * These include checks for definite assignment and unreachable statements.

      * If any errors occur, an empty list will be returned.

      * @returns the list of attributed parse trees

      */

     public Queue<Env<AttrContext>> flow(Queue<Env<AttrContext>> envs) {

         ListBuffer<Env<AttrContext>> results = lb();

         for (Env<AttrContext> env: envs) {

             flow(env, results);

         }

         return stopIfError(results);

     }

     /**

      * Perform dataflow checks on an attributed parse tree.

      */

     public Queue<Env<AttrContext>> flow(Env<AttrContext> env) {

         ListBuffer<Env<AttrContext>> results = lb();

         flow(env, results);

         return stopIfError(results);

     }

     /**

      * Perform dataflow checks on an attributed parse tree.

      */

     protected void flow(Env<AttrContext> env, Queue<Env<AttrContext>> results) {

         try {

             if (errorCount() > 0)

                 return;

             if (relax || compileStates.isDone(env, CompileState.FLOW)) {

                 results.add(env);

                 return;

             }

             if (verboseCompilePolicy)

                 log.printLines(log.noticeWriter, "[flow " + env.enclClass.sym + "]");

             JavaFileObject prev = log.useSource(

                                                 env.enclClass.sym.sourcefile != null ?

                                                 env.enclClass.sym.sourcefile :

                                                 env.toplevel.sourcefile);

             try {

                 make.at(Position.FIRSTPOS);

                 TreeMaker localMake = make.forToplevel(env.toplevel);

                 flow.analyzeTree(env.tree, localMake);

                 compileStates.put(env, CompileState.FLOW);

                 if (errorCount() > 0)

                     return;

                 results.add(env);

             }

             finally {

                 log.useSource(prev);

             }

         }

         finally {

             if (taskListener != null) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.ANALYZE, env.toplevel, env.enclClass.sym);

                 taskListener.finished(e);

             }

         }

     }

     /**

      * Prepare attributed parse trees, in conjunction with their attribution contexts,

      * for source or code generation.

      * If any errors occur, an empty list will be returned.

      * @returns a list containing the classes to be generated

      */

     public Queue<Pair<Env<AttrContext>, JCClassDecl>> desugar(Queue<Env<AttrContext>> envs) {

         ListBuffer<Pair<Env<AttrContext>, JCClassDecl>> results = lb();

         for (Env<AttrContext> env: envs)

             desugar(env, results);

         return stopIfError(results);

     }

     /**

      * Prepare attributed parse trees, in conjunction with their attribution contexts,

      * for source or code generation. If the file was not listed on the command line,

      * the current implicitSourcePolicy is taken into account.

      * The preparation stops as soon as an error is found.

      */

     protected void desugar(final Env<AttrContext> env, Queue<Pair<Env<AttrContext>, JCClassDecl>> results) {

         if (errorCount() > 0)

             return;

         if (implicitSourcePolicy == ImplicitSourcePolicy.NONE

                 && !inputFiles.contains(env.toplevel.sourcefile)) {

             return;

         }

         /**

          * As erasure (TransTypes) destroys information needed in flow analysis,

          * including information in supertypes, we need to ensure that supertypes

          * are processed through attribute and flow before subtypes are translated.

          */

         class ScanNested extends TreeScanner {

             Set<Env<AttrContext>> dependencies = new LinkedHashSet<Env<AttrContext>>();

             public void visitClassDef(JCClassDecl node) {

                 Type st = types.supertype(node.sym.type);

                 if (st.tag == TypeTags.CLASS) {

                     ClassSymbol c = st.tsym.outermostClass();

                     Env<AttrContext> stEnv = enter.getEnv(c);

                     if (stEnv != null && env != stEnv) {

                         if (dependencies.add(stEnv))

                             scan(stEnv.tree);

                     }

                 }

                 super.visitClassDef(node);

             }

         }

         ScanNested scanner = new ScanNested();

         scanner.scan(env.tree);

         for (Env<AttrContext> dep: scanner.dependencies) {

             if (!compileStates.isDone(dep, CompileState.FLOW))

                 flow(attribute(dep));

         }

         //We need to check for error another time as more classes might

         //have been attributed and analyzed at this stage

         if (errorCount() > 0)

             return;

         if (verboseCompilePolicy)

             log.printLines(log.noticeWriter, "[desugar " + env.enclClass.sym + "]");

         JavaFileObject prev = log.useSource(env.enclClass.sym.sourcefile != null ?

                                   env.enclClass.sym.sourcefile :

                                   env.toplevel.sourcefile);

         try {

             //save tree prior to rewriting

             JCTree untranslated = env.tree;

             make.at(Position.FIRSTPOS);

             TreeMaker localMake = make.forToplevel(env.toplevel);

             if (env.tree instanceof JCCompilationUnit) {

                 if (!(stubOutput || sourceOutput || printFlat)) {

                     List<JCTree> pdef = lower.translateTopLevelClass(env, env.tree, localMake);

                     if (pdef.head != null) {

                         assert pdef.tail.isEmpty();

                         results.add(new Pair<Env<AttrContext>, JCClassDecl>(env, (JCClassDecl)pdef.head));

                     }

                 }

                 return;

             }

             if (stubOutput) {

                 //emit stub Java source file, only for compilation

                 //units enumerated explicitly on the command line

                 JCClassDecl cdef = (JCClassDecl)env.tree;

                 if (untranslated instanceof JCClassDecl &&

                     rootClasses.contains((JCClassDecl)untranslated) &&

                     ((cdef.mods.flags & (Flags.PROTECTED|Flags.PUBLIC)) != 0 ||

                      cdef.sym.packge().getQualifiedName() == names.java_lang)) {

                     results.add(new Pair<Env<AttrContext>, JCClassDecl>(env, removeMethodBodies(cdef)));

                 }

                 return;

             }

             env.tree = transTypes.translateTopLevelClass(env.tree, localMake);

             if (errorCount() != 0)

                 return;

             if (sourceOutput) {

                 //emit standard Java source file, only for compilation

                 //units enumerated explicitly on the command line

                 JCClassDecl cdef = (JCClassDecl)env.tree;

                 if (untranslated instanceof JCClassDecl &&

                     rootClasses.contains((JCClassDecl)untranslated)) {

                     results.add(new Pair<Env<AttrContext>, JCClassDecl>(env, cdef));

                 }

                 return;

             }

             //translate out inner classes

             List<JCTree> cdefs = lower.translateTopLevelClass(env, env.tree, localMake);

             if (errorCount() != 0)

                 return;

             //generate code for each class

             for (List<JCTree> l = cdefs; l.nonEmpty(); l = l.tail) {

                 JCClassDecl cdef = (JCClassDecl)l.head;

                 results.add(new Pair<Env<AttrContext>, JCClassDecl>(env, cdef));

             }

         }

         finally {

             log.useSource(prev);

         }

     }

     /** Generates the source or class file for a list of classes.

      * The decision to generate a source file or a class file is

      * based upon the compiler's options.

      * Generation stops if an error occurs while writing files.

      */

     public void generate(Queue<Pair<Env<AttrContext>, JCClassDecl>> queue) {

         generate(queue, null);

     }

     public void generate(Queue<Pair<Env<AttrContext>, JCClassDecl>> queue, Queue<JavaFileObject> results) {

         boolean usePrintSource = (stubOutput || sourceOutput || printFlat);

         for (Pair<Env<AttrContext>, JCClassDecl> x: queue) {

             Env<AttrContext> env = x.fst;

             JCClassDecl cdef = x.snd;

             if (verboseCompilePolicy) {

                 log.printLines(log.noticeWriter, "[generate "

                                + (usePrintSource ? " source" : "code")

                                + " " + cdef.sym + "]");

             }

             if (taskListener != null) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.GENERATE, env.toplevel, cdef.sym);

                 taskListener.started(e);

             }

             JavaFileObject prev = log.useSource(env.enclClass.sym.sourcefile != null ?

                                       env.enclClass.sym.sourcefile :

                                       env.toplevel.sourcefile);

             try {

                 JavaFileObject file;

                 if (usePrintSource)

                     file = printSource(env, cdef);

                 else

                     file = genCode(env, cdef);

                 if (results != null && file != null)

                     results.add(file);

             } catch (IOException ex) {

                 log.error(cdef.pos(), "class.cant.write",

                           cdef.sym, ex.getMessage());

                 return;

             } finally {

                 log.useSource(prev);

             }

             if (taskListener != null) {

                 TaskEvent e = new TaskEvent(TaskEvent.Kind.GENERATE, env.toplevel, cdef.sym);

                 taskListener.finished(e);

             }

         }

     }

         // where

         Map<JCCompilationUnit, Queue<Env<AttrContext>>> groupByFile(Queue<Env<AttrContext>> envs) {

             // use a LinkedHashMap to preserve the order of the original list as much as possible

             Map<JCCompilationUnit, Queue<Env<AttrContext>>> map = new LinkedHashMap<JCCompilationUnit, Queue<Env<AttrContext>>>();

             for (Env<AttrContext> env: envs) {

                 Queue<Env<AttrContext>> sublist = map.get(env.toplevel);

                 if (sublist == null) {

                     sublist = new ListBuffer<Env<AttrContext>>();

                     map.put(env.toplevel, sublist);

                 }

                 sublist.add(env);

             }

             return map;

         }

         JCClassDecl removeMethodBodies(JCClassDecl cdef) {

             final boolean isInterface = (cdef.mods.flags & Flags.INTERFACE) != 0;

             class MethodBodyRemover extends TreeTranslator {

                 public void visitMethodDef(JCMethodDecl tree) {

                     tree.mods.flags &= ~Flags.SYNCHRONIZED;

                     for (JCVariableDecl vd : tree.params)

                         vd.mods.flags &= ~Flags.FINAL;

                     tree.body = null;

                     super.visitMethodDef(tree);

                 }

                 public void visitVarDef(JCVariableDecl tree) {

                     if (tree.init != null && tree.init.type.constValue() == null)

                         tree.init = null;

                     super.visitVarDef(tree);

                 }

                 public void visitClassDef(JCClassDecl tree) {

                     ListBuffer<JCTree> newdefs = lb();

                     for (List<JCTree> it = tree.defs; it.tail != null; it = it.tail) {

                         JCTree t = it.head;

                         switch (t.getTag()) {

                         case JCTree.CLASSDEF:

                             if (isInterface ||

                                 (((JCClassDecl) t).mods.flags & (Flags.PROTECTED|Flags.PUBLIC)) != 0 ||

                                 (((JCClassDecl) t).mods.flags & (Flags.PRIVATE)) == 0 && ((JCClassDecl) t).sym.packge().getQualifiedName() == names.java_lang)

                                 newdefs.append(t);

                             break;

                         case JCTree.METHODDEF:

                             if (isInterface ||

                                 (((JCMethodDecl) t).mods.flags & (Flags.PROTECTED|Flags.PUBLIC)) != 0 ||

                                 ((JCMethodDecl) t).sym.name == names.init ||

                                 (((JCMethodDecl) t).mods.flags & (Flags.PRIVATE)) == 0 && ((JCMethodDecl) t).sym.packge().getQualifiedName() == names.java_lang)

                                 newdefs.append(t);

                             break;

                         case JCTree.VARDEF:

                             if (isInterface || (((JCVariableDecl) t).mods.flags & (Flags.PROTECTED|Flags.PUBLIC)) != 0 ||

                                 (((JCVariableDecl) t).mods.flags & (Flags.PRIVATE)) == 0 && ((JCVariableDecl) t).sym.packge().getQualifiedName() == names.java_lang)

                                 newdefs.append(t);

                             break;

                         default:

                             break;

                         }

                     }

                     tree.defs = newdefs.toList();

                     super.visitClassDef(tree);

                 }

             }

             MethodBodyRemover r = new MethodBodyRemover();

             return r.translate(cdef);

         }

     public void reportDeferredDiagnostics() {

         if (annotationProcessingOccurred

                 && implicitSourceFilesRead

                 && implicitSourcePolicy == ImplicitSourcePolicy.UNSET) {

             if (explicitAnnotationProcessingRequested())

                 log.warning("proc.use.implicit");

             else

                 log.warning("proc.use.proc.or.implicit");

         }

         chk.reportDeferredDiagnostics();

     }

     /** Close the compiler, flushing the logs

      */

     public void close() {

         close(true);

     }

     public void close(boolean disposeNames) {

         rootClasses = null;

         reader = null;

         make = null;

         writer = null;

         enter = null;

         if (todo != null)

             todo.clear();

         todo = null;

         parserFactory = null;

         syms = null;

         source = null;

         attr = null;

         chk = null;

         gen = null;

         flow = null;

         transTypes = null;

         lower = null;

         annotate = null;

         types = null;

         log.flush();

         try {

             fileManager.flush();

         } catch (IOException e) {

             throw new Abort(e);

         } finally {

             if (names != null && disposeNames)

                 names.dispose();

             names = null;

         }

     }

     /** Output for "-verbose" option.

      *  @param key The key to look up the correct internationalized string.

      *  @param arg An argument for substitution into the output string.

      */

     protected void printVerbose(String key, Object arg) {

         Log.printLines(log.noticeWriter, log.getLocalizedString("verbose." + key, arg));

     }

     /** Print numbers of errors and warnings.

      */

     protected void printCount(String kind, int count) {

         if (count != 0) {

             String text;

             if (count == 1)

                 text = log.getLocalizedString("count." + kind, String.valueOf(count));

             else

                 text = log.getLocalizedString("count." + kind + ".plural", String.valueOf(count));

             Log.printLines(log.errWriter, text);

             log.errWriter.flush();

         }

     }

     private static long now() {

         return System.currentTimeMillis();

     }

     private static long elapsed(long then) {

         return now() - then;

     }

     public void initRound(JavaCompiler prev) {

         keepComments = prev.keepComments;

         start_msec = prev.start_msec;

         hasBeenUsed = true;

     }

     public static void enableLogging() {

         Logger logger = Logger.getLogger(com.sun.tools.javac.Main.class.getPackage().getName());

         logger.setLevel(Level.ALL);

         for (Handler h : logger.getParent().getHandlers()) {

             h.setLevel(Level.ALL);

        }

     }

 }