1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package com.sun.tools.jextract;
  24 
  25 import java.nio.file.Path;
  26 import java.nio.file.Paths;
  27 import java.util.ArrayList;
  28 import java.util.HashMap;
  29 import java.util.List;
  30 import java.util.Map;
  31 import java.util.Objects;
  32 import java.util.Optional;
  33 import java.util.logging.Level;
  34 import java.util.logging.Logger;
  35 import java.util.stream.Collectors;
  36 import java.util.stream.Stream;
  37 import com.sun.tools.jextract.parser.Parser;
  38 import com.sun.tools.jextract.tree.HeaderTree;
  39 import com.sun.tools.jextract.tree.SimpleTreeVisitor;
  40 import com.sun.tools.jextract.tree.StructTree;
  41 import com.sun.tools.jextract.tree.Tree;
  42 import com.sun.tools.jextract.tree.TreeMaker;
  43 import com.sun.tools.jextract.tree.TreePhase;
  44 import com.sun.tools.jextract.tree.TreePrinter;
  45 import com.sun.tools.jextract.tree.TypedefTree;
  46 import jdk.internal.clang.Cursor;
  47 
  48 /**
  49  * This visitor handles certain typedef declarations.
  50  *
  51  * 1. Remove redundant typedefs.
  52  * 2. Rename typedef'ed anonymous type definitions like
  53  *        typedef struct { int x; int y; } Point;
  54  */
  55 final class TypedefHandler extends SimpleTreeVisitor<Void, Void>
  56         implements TreePhase {
  57     private final TreeMaker treeMaker = new TreeMaker();
  58 
  59     // Potential Tree instances that will go into transformed HeaderTree
  60     // are collected in this list.
  61     private List<Tree> decls = new ArrayList<>();
  62 
  63     // Tree instances that are to be replaced from "decls" list are
  64     // saved in the following Map. One or more Trees can replace a Tree.
  65     private final Map<Cursor, List<Tree>> replacements = new HashMap<>();
  66 
  67     private final Log log;
  68 
  69     public TypedefHandler(Context ctx) {
  70         this.log = ctx.log;
  71     }
  72 
  73     @Override
  74     public HeaderTree transform(HeaderTree ht) {
  75         // Process all header declarations are collect potential
  76         // declarations that will go into transformed HeaderTree
  77         // into the this.decls field.
  78         ht.accept(this, null);
  79 
  80         // Replace trees from this.decls with Trees found in this.replacements.
  81         // We need this two step process so that named StructTree instances
  82         // will replace with original unnamed StructTree instances.
  83         List<Tree> newDecls = decls.stream().flatMap(tx -> {
  84             if (replacements.containsKey(tx.cursor())) {
  85                 return replacements.get(tx.cursor()).stream();
  86             } else {
  87                 return Stream.of(tx);
  88             }
  89         }).collect(Collectors.toList());
  90 
  91         return treeMaker.createHeader(ht.cursor(), ht.path(), newDecls);
  92     }
  93 
  94     @Override
  95     public Void defaultAction(Tree tree, Void v) {
  96         decls.add(tree);
  97         return null;
  98     }
  99 
 100     @Override
 101     public Void visitHeader(HeaderTree ht, Void v) {
 102         ht.declarations().forEach(decl -> decl.accept(this, null));
 103         return null;
 104     }
 105 
 106     @Override
 107     public Void visitTypedef(TypedefTree tt, Void v) {
 108         Optional<Tree> def = tt.typeDefinition();
 109         if (def.isPresent()) {
 110             Tree defTree = def.get();
 111             if (defTree instanceof StructTree && defTree.name().isEmpty()) {
 112                 /*
 113                  * typedef struct { int x; int y; } Point
 114                  *
 115                  * is mapped to two Cursors by clang. First one for anonymous struct decl.
 116                  * and second one for typedef decl. We map it as a single named struct
 117                  * declaration.
 118                  *
 119                  * There may be more than one typedef on underlying anonymous struct/union.
 120                  * Example:
 121                  *
 122                  * typedef struct { int x; int y; } Point;
 123                  * typedef Point Vector;
 124                  */
 125 
 126                 Cursor dc = defTree.cursor();
 127                 List<Tree> trees = replacements.computeIfAbsent(dc, k -> new ArrayList<>());
 128                 trees.add(((StructTree)defTree).withName(tt.name()));
 129                 log.print(Level.FINE, () -> "Typedef " + defTree.type().spelling() + " as " + tt.name());    
 130                 return null;
 131             } else if (defTree.name().equals(tt.name())) {
 132                 /*
 133                  * Remove redundant typedef like:
 134                  *
 135                  * typedef struct Point { int x; int y; } Point
 136                  * typedef enum Color { R, G, B} Color
 137                  * typedef struct Undef Undef
 138                  */
 139                 return null;
 140             }
 141         }
 142 
 143         /*
 144          * There are typedefs on built-in types like struct __va_list_tag. These
 145          * are not exposed as declaration cursor for any headers, but are available
 146          * from Type objects. We've to walk and check null file path to detect these
 147          * Cursors and create Trees.
 148          */
 149         Utils.getBuiltinRecordTypes(tt.type()).forEach(c -> {
 150             decls.add(treeMaker.createTree(c));
 151         });
 152 
 153         decls.add(tt);
 154         return null;
 155     }
 156 
 157     // test main to manually check this visitor
 158     public static void main(String[] args) {
 159         if (args.length == 0) {
 160             System.err.println("Expected a header file");
 161             return;
 162         }
 163 
 164         Context context = Context.createDefault();
 165         Parser p = new Parser(context, true);
 166         Path builtinInc = Paths.get(System.getProperty("java.home"), "conf", "jextract");
 167         List<String> clangArgs = List.of("-I" + builtinInc);
 168         HeaderTree header = p.parse(Paths.get(args[0]), clangArgs);
 169         TreePrinter printer = new TreePrinter();
 170         TypedefHandler handler = new TypedefHandler(context);
 171         handler.transform(header).accept(printer, null);
 172     }
 173 }