1 /*
2 * Copyright (c) 2009, 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
24
25 package org.graalvm.compiler.asm;
26
27 import java.util.ArrayList;
28 import java.util.HashMap;
29 import java.util.List;
30 import java.util.Map;
31 import java.util.function.Consumer;
32
33 import jdk.vm.ci.code.Register;
34 import jdk.vm.ci.code.StackSlot;
35 import jdk.vm.ci.code.TargetDescription;
36
37 /**
38 * The platform-independent base class for the assembler.
39 */
40 public abstract class Assembler {
41
42 public abstract static class CodeAnnotation {
43 /**
44 * The position (bytes from the beginning of the method) of the annotated instruction.
45 */
46 public final int instructionPosition;
47
48 protected CodeAnnotation(int instructionStartPosition) {
49 this.instructionPosition = instructionStartPosition;
50 }
51 }
52
53 public final TargetDescription target;
54 private List<LabelHint> jumpDisplacementHints;
55
56 /**
57 * Backing code buffer.
58 */
59 private final Buffer codeBuffer;
60
61 protected Consumer<CodeAnnotation> codePatchingAnnotationConsumer;
62
63 public Assembler(TargetDescription target) {
64 this.target = target;
65 this.codeBuffer = new Buffer(target.arch.getByteOrder());
66 }
67
68 public void setCodePatchingAnnotationConsumer(Consumer<CodeAnnotation> codeAnnotationConsumer) {
69 assert this.codePatchingAnnotationConsumer == null : "overwriting existing value";
70 this.codePatchingAnnotationConsumer = codeAnnotationConsumer;
71 }
72
73 /**
74 * Returns the current position of the underlying code buffer.
75 *
76 * @return current position in code buffer
77 */
78 public int position() {
79 return codeBuffer.position();
80 }
81
82 public final void emitByte(int x) {
83 codeBuffer.emitByte(x);
84 }
85
86 public final void emitShort(int x) {
87 codeBuffer.emitShort(x);
88 }
89
90 public final void emitInt(int x) {
91 codeBuffer.emitInt(x);
92 }
93
94 public final void emitLong(long x) {
95 codeBuffer.emitLong(x);
96 }
97
98 public final void emitByte(int b, int pos) {
99 codeBuffer.emitByte(b, pos);
100 }
101
102 public final void emitShort(int b, int pos) {
103 codeBuffer.emitShort(b, pos);
104 }
105
106 public final void emitInt(int b, int pos) {
107 codeBuffer.emitInt(b, pos);
108 }
109
110 public final void emitLong(long b, int pos) {
111 codeBuffer.emitLong(b, pos);
112 }
113
114 public final int getByte(int pos) {
115 return codeBuffer.getByte(pos);
116 }
117
118 public final int getShort(int pos) {
119 return codeBuffer.getShort(pos);
120 }
121
122 public final int getInt(int pos) {
123 return codeBuffer.getInt(pos);
124 }
125
126 private static final String NEWLINE = System.getProperty("line.separator");
127
128 /**
129 * Some GPU architectures have a text based encoding.
130 */
131 public final void emitString(String x) {
132 emitString0("\t"); // XXX REMOVE ME pretty-printing
133 emitString0(x);
134 emitString0(NEWLINE);
135 }
136
137 // XXX for pretty-printing
138 public final void emitString0(String x) {
139 codeBuffer.emitBytes(x.getBytes(), 0, x.length());
140 }
141
142 public void emitString(String s, int pos) {
143 codeBuffer.emitBytes(s.getBytes(), pos);
144 }
145
146 /**
147 * Closes this assembler. No extra data can be written to this assembler after this call.
148 *
149 * @param trimmedCopy if {@code true}, then a copy of the underlying byte array up to (but not
150 * including) {@code position()} is returned
151 * @return the data in this buffer or a trimmed copy if {@code trimmedCopy} is {@code true}
152 */
153 public byte[] close(boolean trimmedCopy) {
154 return codeBuffer.close(trimmedCopy);
155 }
156
157 public void bind(Label l) {
158 assert !l.isBound() : "can bind label only once";
159 l.bind(position());
160 l.patchInstructions(this);
161 }
162
163 public abstract void align(int modulus);
164
165 public abstract void jmp(Label l);
166
167 protected abstract void patchJumpTarget(int branch, int jumpTarget);
168
169 private Map<Label, String> nameMap;
170
171 /**
172 * Creates a name for a label.
173 *
174 * @param l the label for which a name is being created
175 * @param id a label identifier that is unique with the scope of this assembler
176 * @return a label name in the form of "L123"
177 */
178 protected String createLabelName(Label l, int id) {
179 return "L" + id;
180 }
181
182 /**
183 * Gets a name for a label, creating it if it does not yet exist. By default, the returned name
184 * is only unique with the scope of this assembler.
185 */
186 public String nameOf(Label l) {
187 if (nameMap == null) {
188 nameMap = new HashMap<>();
189 }
190 String name = nameMap.get(l);
191 if (name == null) {
192 name = createLabelName(l, nameMap.size());
193 nameMap.put(l, name);
194 }
195 return name;
196 }
197
198 /**
199 * This is used by the CompilationResultBuilder to convert a {@link StackSlot} to an
200 * {@link AbstractAddress}.
201 */
202 public abstract AbstractAddress makeAddress(Register base, int displacement);
203
204 /**
205 * Returns a target specific placeholder address that can be used for code patching.
206 *
207 * @param instructionStartPosition The start of the instruction, i.e., the value that is used as
208 * the key for looking up placeholder patching information.
209 */
210 public abstract AbstractAddress getPlaceholder(int instructionStartPosition);
211
212 /**
213 * Emits a NOP instruction to advance the current PC.
214 */
215 public abstract void ensureUniquePC();
216
217 public void reset() {
218 codeBuffer.reset();
219 captureLabelPositions();
220 }
221
222 private void captureLabelPositions() {
223 if (jumpDisplacementHints == null) {
224 return;
225 }
226 for (LabelHint request : this.jumpDisplacementHints) {
227 request.capture();
228 }
229 }
230
231 public LabelHint requestLabelHint(Label label) {
232 if (jumpDisplacementHints == null) {
233 jumpDisplacementHints = new ArrayList<>();
234 }
235 LabelHint hint = new LabelHint(label, position());
236 this.jumpDisplacementHints.add(hint);
237 return hint;
238 }
239
240 public InstructionCounter getInstructionCounter() {
241 throw new UnsupportedOperationException("Instruction counter is not implemented for " + this);
242 }
243
244 public static class LabelHint {
245 private Label label;
246 private int forPosition;
247 private int capturedTarget = -1;
248
249 protected LabelHint(Label label, int lastPosition) {
250 super();
251 this.label = label;
252 this.forPosition = lastPosition;
253 }
254
255 protected void capture() {
256 this.capturedTarget = label.position();
257 }
258
259 public int getTarget() {
260 assert isValid();
261 return capturedTarget;
262 }
263
264 public int getPosition() {
265 assert isValid();
266 return forPosition;
267 }
268
269 public boolean isValid() {
270 return capturedTarget >= 0;
271 }
272 }
273
274 /**
275 * Instruction counter class which gives the user of the assembler to count different kinds of
276 * instructions in the generated assembler code.
277 */
278 public interface InstructionCounter {
279 String[] getSupportedInstructionTypes();
280
281 int[] countInstructions(String[] instructionTypes, int beginPc, int endPc);
282 }
283 }