1 /*
2 * Copyright (c) 2009, 2012, 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 org.graalvm.compiler.lir.alloc.lsra;
24
25 import static jdk.vm.ci.code.ValueUtil.asRegister;
26 import static jdk.vm.ci.code.ValueUtil.isRegister;
27
28 import java.util.ArrayList;
29 import java.util.EnumSet;
30
31 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
32 import org.graalvm.compiler.core.common.cfg.BlockMap;
33 import org.graalvm.compiler.debug.DebugContext;
34 import org.graalvm.compiler.debug.GraalError;
35 import org.graalvm.compiler.debug.Indent;
36 import org.graalvm.compiler.lir.InstructionValueConsumer;
37 import org.graalvm.compiler.lir.LIRInstruction;
38 import org.graalvm.compiler.lir.LIRInstruction.OperandFlag;
39 import org.graalvm.compiler.lir.LIRInstruction.OperandMode;
40
41 import jdk.vm.ci.code.Register;
42 import jdk.vm.ci.meta.Value;
43
44 /**
45 */
46 final class RegisterVerifier {
47
48 LinearScan allocator;
49 ArrayList<AbstractBlockBase<?>> workList; // all blocks that must be processed
50 BlockMap<Interval[]> savedStates; // saved information of previous check
51
52 // simplified access to methods of LinearScan
53 Interval intervalAt(Value operand) {
54 return allocator.intervalFor(operand);
55 }
56
57 // currently, only registers are processed
58 int stateSize() {
59 return allocator.maxRegisterNumber() + 1;
60 }
61
62 // accessors
63 Interval[] stateForBlock(AbstractBlockBase<?> block) {
64 return savedStates.get(block);
65 }
66
67 void setStateForBlock(AbstractBlockBase<?> block, Interval[] savedState) {
68 savedStates.put(block, savedState);
69 }
70
71 void addToWorkList(AbstractBlockBase<?> block) {
72 if (!workList.contains(block)) {
73 workList.add(block);
74 }
75 }
76
77 RegisterVerifier(LinearScan allocator) {
78 this.allocator = allocator;
79 workList = new ArrayList<>(16);
80 this.savedStates = new BlockMap<>(allocator.getLIR().getControlFlowGraph());
81
82 }
83
84 @SuppressWarnings("try")
85 void verify(AbstractBlockBase<?> start) {
86 DebugContext debug = allocator.getDebug();
87 try (DebugContext.Scope s = debug.scope("RegisterVerifier")) {
88 // setup input registers (method arguments) for first block
89 Interval[] inputState = new Interval[stateSize()];
90 setStateForBlock(start, inputState);
91 addToWorkList(start);
92
93 // main loop for verification
94 do {
95 AbstractBlockBase<?> block = workList.get(0);
96 workList.remove(0);
97
98 processBlock(block);
99 } while (!workList.isEmpty());
100 }
101 }
102
103 @SuppressWarnings("try")
104 private void processBlock(AbstractBlockBase<?> block) {
105 DebugContext debug = allocator.getDebug();
106 try (Indent indent = debug.logAndIndent("processBlock B%d", block.getId())) {
107 // must copy state because it is modified
108 Interval[] inputState = copy(stateForBlock(block));
109
110 try (Indent indent2 = debug.logAndIndent("Input-State of intervals:")) {
111 printState(inputState);
112 }
113
114 // process all operations of the block
115 processOperations(block, inputState);
116
117 try (Indent indent2 = debug.logAndIndent("Output-State of intervals:")) {
118 printState(inputState);
119 }
120
121 // iterate all successors
122 for (AbstractBlockBase<?> succ : block.getSuccessors()) {
123 processSuccessor(succ, inputState);
124 }
125 }
126 }
127
128 protected void printState(Interval[] inputState) {
129 DebugContext debug = allocator.getDebug();
130 for (int i = 0; i < stateSize(); i++) {
131 Register reg = allocator.getRegisters().get(i);
132 assert reg.number == i;
133 if (inputState[i] != null) {
134 debug.log(" %6s %4d -- %s", reg, inputState[i].operandNumber, inputState[i]);
135 } else {
136 debug.log(" %6s __", reg);
137 }
138 }
139 }
140
141 private void processSuccessor(AbstractBlockBase<?> block, Interval[] inputState) {
142 DebugContext debug = allocator.getDebug();
143 Interval[] savedState = stateForBlock(block);
144
145 if (savedState != null) {
146 // this block was already processed before.
147 // check if new inputState is consistent with savedState
148
149 boolean savedStateCorrect = true;
150 for (int i = 0; i < stateSize(); i++) {
151 if (inputState[i] != savedState[i]) {
152 // current inputState and previous savedState assume a different
153 // interval in this register . assume that this register is invalid
154 if (savedState[i] != null) {
155 // invalidate old calculation only if it assumed that
156 // register was valid. when the register was already invalid,
157 // then the old calculation was correct.
158 savedStateCorrect = false;
159 savedState[i] = null;
160
161 debug.log("processSuccessor B%d: invalidating slot %d", block.getId(), i);
162 }
163 }
164 }
165
166 if (savedStateCorrect) {
167 // already processed block with correct inputState
168 debug.log("processSuccessor B%d: previous visit already correct", block.getId());
169 } else {
170 // must re-visit this block
171 debug.log("processSuccessor B%d: must re-visit because input state changed", block.getId());
172 addToWorkList(block);
173 }
174
175 } else {
176 // block was not processed before, so set initial inputState
177 debug.log("processSuccessor B%d: initial visit", block.getId());
178
179 setStateForBlock(block, copy(inputState));
180 addToWorkList(block);
181 }
182 }
183
184 static Interval[] copy(Interval[] inputState) {
185 return inputState.clone();
186 }
187
188 static void statePut(DebugContext debug, Interval[] inputState, Value location, Interval interval) {
189 if (location != null && isRegister(location)) {
190 Register reg = asRegister(location);
191 int regNum = reg.number;
192 if (interval != null) {
193 debug.log("%s = %s", reg, interval.operand);
194 } else if (inputState[regNum] != null) {
195 debug.log("%s = null", reg);
196 }
197
198 inputState[regNum] = interval;
199 }
200 }
201
202 static boolean checkState(AbstractBlockBase<?> block, LIRInstruction op, Interval[] inputState, Value operand, Value reg, Interval interval) {
203 if (reg != null && isRegister(reg)) {
204 if (inputState[asRegister(reg).number] != interval) {
205 throw new GraalError(
206 "Error in register allocation: operation (%s) in block %s expected register %s (operand %s) to contain the value of interval %s but data-flow says it contains interval %s",
207 op, block, reg, operand, interval, inputState[asRegister(reg).number]);
208 }
209 }
210 return true;
211 }
212
213 void processOperations(AbstractBlockBase<?> block, final Interval[] inputState) {
214 ArrayList<LIRInstruction> ops = allocator.getLIR().getLIRforBlock(block);
215 DebugContext debug = allocator.getDebug();
216 InstructionValueConsumer useConsumer = new InstructionValueConsumer() {
217
218 @Override
219 public void visitValue(LIRInstruction op, Value operand, OperandMode mode, EnumSet<OperandFlag> flags) {
220 // we skip spill moves inserted by the spill position optimization
221 if (LinearScan.isVariableOrRegister(operand) && allocator.isProcessed(operand) && op.id() != LinearScan.DOMINATOR_SPILL_MOVE_ID) {
222 Interval interval = intervalAt(operand);
223 if (op.id() != -1) {
224 interval = interval.getSplitChildAtOpId(op.id(), mode, allocator);
225 }
226
227 assert checkState(block, op, inputState, interval.operand, interval.location(), interval.splitParent());
228 }
229 }
230 };
231
232 InstructionValueConsumer defConsumer = (op, operand, mode, flags) -> {
233 if (LinearScan.isVariableOrRegister(operand) && allocator.isProcessed(operand)) {
234 Interval interval = intervalAt(operand);
235 if (op.id() != -1) {
236 interval = interval.getSplitChildAtOpId(op.id(), mode, allocator);
237 }
238
239 statePut(debug, inputState, interval.location(), interval.splitParent());
240 }
241 };
242
243 // visit all instructions of the block
244 for (int i = 0; i < ops.size(); i++) {
245 final LIRInstruction op = ops.get(i);
246
247 if (debug.isLogEnabled()) {
248 debug.log("%s", op.toStringWithIdPrefix());
249 }
250
251 // check if input operands are correct
252 op.visitEachInput(useConsumer);
253 // invalidate all caller save registers at calls
254 if (op.destroysCallerSavedRegisters()) {
255 for (Register r : allocator.getRegisterAllocationConfig().getRegisterConfig().getCallerSaveRegisters()) {
256 statePut(debug, inputState, r.asValue(), null);
257 }
258 }
259 op.visitEachAlive(useConsumer);
260 // set temp operands (some operations use temp operands also as output operands, so
261 // can't set them null)
262 op.visitEachTemp(defConsumer);
263 // set output operands
264 op.visitEachOutput(defConsumer);
265 }
266 }
267 }