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.trace.lsra;
24
25 import static org.graalvm.compiler.lir.alloc.trace.lsra.TraceLinearScanPhase.isVariableOrRegister;
26 import static jdk.vm.ci.code.ValueUtil.asRegister;
27 import static jdk.vm.ci.code.ValueUtil.isRegister;
28
29 import java.util.ArrayList;
30 import java.util.EnumSet;
31 import java.util.List;
32
33 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
34 import org.graalvm.compiler.core.common.util.ArrayMap;
35 import org.graalvm.compiler.debug.Debug;
36 import org.graalvm.compiler.debug.Debug.Scope;
37 import org.graalvm.compiler.debug.GraalError;
38 import org.graalvm.compiler.debug.Indent;
39 import org.graalvm.compiler.lir.InstructionValueConsumer;
40 import org.graalvm.compiler.lir.LIRInstruction;
41 import org.graalvm.compiler.lir.LIRInstruction.OperandFlag;
42 import org.graalvm.compiler.lir.LIRInstruction.OperandMode;
43 import org.graalvm.compiler.lir.alloc.trace.lsra.TraceLinearScanPhase.TraceLinearScan;
44
45 import jdk.vm.ci.code.Register;
46 import jdk.vm.ci.meta.Value;
47
48 /**
49 */
50 final class RegisterVerifier {
51
52 TraceLinearScan allocator;
53 List<AbstractBlockBase<?>> workList; // all blocks that must be processed
54 ArrayMap<TraceInterval[]> savedStates; // saved information of previous check
55
56 // simplified access to methods of LinearScan
57 TraceInterval intervalAt(Value operand) {
58 return allocator.intervalFor(operand);
59 }
60
61 // currently, only registers are processed
62 int stateSize() {
63 return allocator.numRegisters();
64 }
65
66 // accessors
67 TraceInterval[] stateForBlock(AbstractBlockBase<?> block) {
68 return savedStates.get(block.getId());
69 }
70
71 void setStateForBlock(AbstractBlockBase<?> block, TraceInterval[] savedState) {
72 savedStates.put(block.getId(), savedState);
73 }
74
75 void addToWorkList(AbstractBlockBase<?> block) {
76 if (!workList.contains(block)) {
77 workList.add(block);
78 }
79 }
80
81 RegisterVerifier(TraceLinearScan allocator) {
82 this.allocator = allocator;
83 workList = new ArrayList<>(16);
84 this.savedStates = new ArrayMap<>();
85
86 }
87
88 @SuppressWarnings("try")
89 void verify(AbstractBlockBase<?> start) {
90 try (Scope s = Debug.scope("RegisterVerifier")) {
91 // setup input registers (method arguments) for first block
92 TraceInterval[] inputState = new TraceInterval[stateSize()];
93 setStateForBlock(start, inputState);
94 addToWorkList(start);
95
96 // main loop for verification
97 do {
98 AbstractBlockBase<?> block = workList.get(0);
99 workList.remove(0);
100
101 processBlock(block);
102 } while (!workList.isEmpty());
103 }
104 }
105
106 @SuppressWarnings("try")
107 private void processBlock(AbstractBlockBase<?> block) {
108 try (Indent indent = Debug.logAndIndent("processBlock B%d", block.getId())) {
109 // must copy state because it is modified
110 TraceInterval[] inputState = copy(stateForBlock(block));
111
112 try (Indent indent2 = Debug.logAndIndent("Input-State of intervals:")) {
113 printState(inputState);
114 }
115
116 // process all operations of the block
117 processOperations(block, inputState);
118
119 try (Indent indent2 = Debug.logAndIndent("Output-State of intervals:")) {
120 printState(inputState);
121 }
122
123 // iterate all successors
124 for (AbstractBlockBase<?> succ : block.getSuccessors()) {
125 processSuccessor(succ, inputState);
126 }
127 }
128 }
129
130 protected void printState(TraceInterval[] inputState) {
131 for (int i = 0; i < stateSize(); i++) {
132 Register reg = allocator.getRegisters().get(i);
133 assert reg.number == i;
134 if (inputState[i] != null) {
135 Debug.log(" %6s %4d -- %s", reg, inputState[i].operandNumber, inputState[i]);
136 } else {
137 Debug.log(" %6s __", reg);
138 }
139 }
140 }
141
142 private void processSuccessor(AbstractBlockBase<?> block, TraceInterval[] inputState) {
143 TraceInterval[] 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 TraceInterval[] copy(TraceInterval[] inputState) {
185 return inputState.clone();
186 }
187
188 static void statePut(TraceInterval[] inputState, Value location, TraceInterval 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, TraceInterval[] inputState, Value operand, Value reg, TraceInterval 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 TraceInterval[] inputState) {
214 List<LIRInstruction> ops = allocator.getLIR().getLIRforBlock(block);
215 InstructionValueConsumer useConsumer = new InstructionValueConsumer() {
216
217 @Override
218 public void visitValue(LIRInstruction op, Value operand, OperandMode mode, EnumSet<OperandFlag> flags) {
219 // we skip spill moves inserted by the spill position optimization
220 if (isVariableOrRegister(operand) && allocator.isProcessed(operand) && op.id() != TraceLinearScanPhase.DOMINATOR_SPILL_MOVE_ID) {
221 TraceInterval interval = intervalAt(operand);
222 if (op.id() != -1) {
223 interval = interval.getSplitChildAtOpId(op.id(), mode);
224 }
225
226 assert checkState(block, op, inputState, interval.operand, interval.location(), interval.splitParent());
227 }
228 }
229 };
230
231 InstructionValueConsumer defConsumer = (op, operand, mode, flags) -> {
232 if (isVariableOrRegister(operand) && allocator.isProcessed(operand)) {
233 TraceInterval interval = intervalAt(operand);
234 if (op.id() != -1) {
235 interval = interval.getSplitChildAtOpId(op.id(), mode);
236 }
237
238 statePut(inputState, interval.location(), interval.splitParent());
239 }
240 };
241
242 // visit all instructions of the block
243 for (int i = 0; i < ops.size(); i++) {
244 final LIRInstruction op = ops.get(i);
245
246 if (Debug.isLogEnabled()) {
247 Debug.log("%s", op.toStringWithIdPrefix());
248 }
249
250 // check if input operands are correct
251 op.visitEachInput(useConsumer);
252 // invalidate all caller save registers at calls
253 if (op.destroysCallerSavedRegisters()) {
254 for (Register r : allocator.getRegisterAllocationConfig().getRegisterConfig().getCallerSaveRegisters()) {
255 statePut(inputState, r.asValue(), null);
256 }
257 }
258 op.visitEachAlive(useConsumer);
259 // set temp operands (some operations use temp operands also as output operands, so
260 // can't set them null)
261 op.visitEachTemp(defConsumer);
262 // set output operands
263 op.visitEachOutput(defConsumer);
264 }
265 }
266 }