1 /*
2 * Copyright (c) 2020, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 package jdk.internal.jextract.impl;
28
29 import jdk.incubator.foreign.GroupLayout;
30 import jdk.incubator.foreign.MemoryLayout;
31 import jdk.incubator.jextract.Declaration;
32 import jdk.internal.clang.Cursor;
33 import jdk.internal.clang.Type;
34
35 import java.util.ArrayList;
36 import java.util.List;
37
38 /**
39 * MemoryLayout computer for C structs.
40 */
41 final class StructLayoutComputer extends RecordLayoutComputer {
42 private long offset;
43 private long actualSize = 0L;
44 // List to collect bitfield fields to process later, may be null
45 private List<Declaration> bitfieldDecls;
46 private List<MemoryLayout> bitfieldLayouts;
47
48 StructLayoutComputer(TypeMaker typeMaker, long offsetInParent, Type parent, Type type) {
49 super(typeMaker, parent, type);
50 this.offset = offsetInParent;
51 }
52
53 @Override
54 void addField(Declaration declaration) {
55 if (bitfieldDecls != null) {
56 bitfieldDecls.add(declaration);
57 MemoryLayout layout = null;
58 if (declaration instanceof Declaration.Scoped scoped) {
59 layout = scoped.layout().orElse(null);
60 } else if (declaration instanceof Declaration.Variable var) {
61 layout = var.layout().orElse(null);
62 }
63 if (layout != null) {
64 bitfieldLayouts.add(declaration.name().isEmpty() ? layout : layout.withName(declaration.name()));
65 }
66 } else {
67 super.addField(declaration);
68 }
69 }
70
71 @Override
72 void addPadding(long bits) {
73 if (bitfieldDecls != null) {
74 bitfieldLayouts.add(MemoryLayout.paddingLayout(bits));
75 } else {
76 super.addPadding(bits);
77 }
78 }
79
80 @Override
81 void startBitfield() {
82 /*
83 * In a struct, a bitfield field is seen after a non-bitfield.
84 * Initialize bitfieldLayouts list to collect this and subsequent
85 * bitfield layouts.
86 */
87 if (bitfieldDecls == null) {
88 bitfieldDecls = new ArrayList<>();
89 bitfieldLayouts = new ArrayList<>();
90 }
91 }
92
93 @Override
94 void processField(Cursor c) {
95 boolean isBitfield = c.isBitField();
96 long expectedOffset = offsetOf(parent, c);
97 if (expectedOffset > offset) {
98 addPadding(expectedOffset - offset);
99 actualSize += (expectedOffset - offset);
100 offset = expectedOffset;
101 }
102
103 if (isBitfield) {
104 startBitfield();
105 } else { // !isBitfield
106 /*
107 * We may be crossing from bit fields to non-bitfield field.
108 *
109 * struct Foo {
110 * int i:12;
111 * int j:20;
112 * int k; // <-- processing this
113 * int m;
114 * }
115 */
116 handleBitfields();
117 }
118
119 addField(offset, parent, c);
120 long size = fieldSize(c);
121 offset += size;
122 actualSize += size;
123 }
124
125 @Override
126 jdk.incubator.jextract.Type.Declared finishRecord(String anonName) {
127 // pad at the end, if any
128 long expectedSize = type.size() * 8;
129 if (actualSize < expectedSize) {
130 addPadding(expectedSize - actualSize);
131 }
132
133 /*
134 * Handle bitfields at the end, if any.
135 *
136 * struct Foo {
137 * int i,j, k;
138 * int f:10;
139 * int pad:12;
140 * }
141 */
142 handleBitfields();
143
144 MemoryLayout[] fields = fieldLayouts.toArray(new MemoryLayout[0]);
145 GroupLayout g = MemoryLayout.structLayout(fields);
146 if (!cursor.spelling().isEmpty()) {
147 g = g.withName(cursor.spelling());
148 } else if (anonName != null) {
149 g = g.withName(anonName);
150 }
151 return jdk.incubator.jextract.Type.declared(Declaration.struct(TreeMaker.CursorPosition.of(cursor), cursor.spelling(), g, fieldDecls.stream().toArray(Declaration[]::new)));
152 }
153
154 // process bitfields if any and clear bitfield layouts
155 private void handleBitfields() {
156 if (bitfieldDecls != null) {
157 List<MemoryLayout> prevBitfieldLayouts = bitfieldLayouts;
158 List<Declaration> prevBitfieldDecls = bitfieldDecls;
159 bitfieldDecls = null;
160 if (!prevBitfieldDecls.isEmpty()) {
161 addField(bitfield(prevBitfieldLayouts, prevBitfieldDecls.toArray(new Declaration.Variable[0])));
162 }
163 }
164 }
165 }