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 jdk.vm.ci.code.ValueUtil.asRegister;
26 import static jdk.vm.ci.code.ValueUtil.isRegister;
27 import static org.graalvm.compiler.lir.LIRValueUtil.asVariable;
28 import static org.graalvm.compiler.lir.alloc.trace.lsra.TraceLinearScanPhase.isVariableOrRegister;
29
30 import java.util.ArrayList;
31 import java.util.EnumSet;
32
33 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
34 import org.graalvm.compiler.core.common.cfg.BlockMap;
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.Variable;
44 import org.graalvm.compiler.lir.alloc.trace.lsra.TraceLinearScanPhase.TraceLinearScan;
45
46 import jdk.vm.ci.code.Register;
47 import jdk.vm.ci.meta.Value;
48
49 /**
50 */
51 final class RegisterVerifier {
52
53 TraceLinearScan allocator;
54 ArrayList<AbstractBlockBase<?>> workList; // all blocks that must be processed
55 BlockMap<TraceInterval[]> savedStates; // saved information of previous check
56
57 // simplified access to methods of LinearScan
58 TraceInterval intervalAt(Variable operand) {
59 return allocator.intervalFor(operand);
60 }
61
62 // currently, only registers are processed
63 int stateSize() {
64 return allocator.numRegisters();
65 }
66
67 // accessors
68 TraceInterval[] stateForBlock(AbstractBlockBase<?> block) {
69 return savedStates.get(block);
70 }
71
72 void setStateForBlock(AbstractBlockBase<?> block, TraceInterval[] savedState) {
73 savedStates.put(block, savedState);
74 }
75
76 void addToWorkList(AbstractBlockBase<?> block) {
77 if (!workList.contains(block)) {
78 workList.add(block);
79 }
80 }
81
82 RegisterVerifier(TraceLinearScan allocator) {
83 this.allocator = allocator;
84 workList = new ArrayList<>(16);
85 this.savedStates = new BlockMap<>(allocator.getLIR().getControlFlowGraph());
86
87 }
88
89 @SuppressWarnings("try")
90 void verify(AbstractBlockBase<?> start) {
91 try (Scope s = Debug.scope("RegisterVerifier")) {
92 // setup input registers (method arguments) for first block
93 TraceInterval[] inputState = new TraceInterval[stateSize()];
94 setStateForBlock(start, inputState);
95 addToWorkList(start);
96
97 // main loop for verification
98 do {
99 AbstractBlockBase<?> block = workList.get(0);
100 workList.remove(0);
101
102 processBlock(block);
103 } while (!workList.isEmpty());
104 }
105 }
106
107 @SuppressWarnings("try")
108 private void processBlock(AbstractBlockBase<?> block) {
109 try (Indent indent = Debug.logAndIndent("processBlock B%d", block.getId())) {
110 // must copy state because it is modified
111 TraceInterval[] inputState = copy(stateForBlock(block));
112
113 try (Indent indent2 = Debug.logAndIndent("Input-State of intervals:")) {
114 printState(inputState);
115 }
116
117 // process all operations of the block
118 processOperations(block, inputState);
119
120 try (Indent indent2 = Debug.logAndIndent("Output-State of intervals:")) {
121 printState(inputState);
122 }
123
124 // iterate all successors
125 for (AbstractBlockBase<?> succ : block.getSuccessors()) {
126 processSuccessor(succ, inputState);
127 }
128 }
129 }
130
131 protected void printState(TraceInterval[] inputState) {
132 for (int i = 0; i < stateSize(); i++) {
133 Register reg = allocator.getRegisters().get(i);
134 assert reg.number == i;
135 if (inputState[i] != null) {
136 Debug.log(" %6s %4d -- %s", reg, inputState[i].operandNumber, inputState[i]);
137 } else {
138 Debug.log(" %6s __", reg);
139 }
140 }
141 }
142
143 private void processSuccessor(AbstractBlockBase<?> block, TraceInterval[] inputState) {
144 TraceInterval[] savedState = stateForBlock(block);
145
146 if (savedState != null) {
147 // this block was already processed before.
148 // check if new inputState is consistent with savedState
149
150 boolean savedStateCorrect = true;
151 for (int i = 0; i < stateSize(); i++) {
152 if (inputState[i] != savedState[i]) {
153 // current inputState and previous savedState assume a different
154 // interval in this register . assume that this register is invalid
155 if (savedState[i] != null) {
156 // invalidate old calculation only if it assumed that
157 // register was valid. when the register was already invalid,
158 // then the old calculation was correct.
159 savedStateCorrect = false;
160 savedState[i] = null;
161
162 Debug.log("processSuccessor B%d: invalidating slot %d", block.getId(), i);
163 }
164 }
165 }
166
167 if (savedStateCorrect) {
168 // already processed block with correct inputState
169 Debug.log("processSuccessor B%d: previous visit already correct", block.getId());
170 } else {
171 // must re-visit this block
172 Debug.log("processSuccessor B%d: must re-visit because input state changed", block.getId());
173 addToWorkList(block);
174 }
175
176 } else {
177 // block was not processed before, so set initial inputState
178 Debug.log("processSuccessor B%d: initial visit", block.getId());
179
180 setStateForBlock(block, copy(inputState));
181 addToWorkList(block);
182 }
183 }
184
185 static TraceInterval[] copy(TraceInterval[] inputState) {
186 return inputState.clone();
187 }
188
189 static void statePut(TraceInterval[] inputState, Value location, TraceInterval interval) {
190 if (location != null && isRegister(location)) {
191 Register reg = asRegister(location);
192 int regNum = reg.number;
193 if (interval != null) {
194 Debug.log("%s = v%d", reg, interval.operandNumber);
195 } else if (inputState[regNum] != null) {
196 Debug.log("%s = null", reg);
197 }
198
199 inputState[regNum] = interval;
200 }
201 }
202
203 static boolean checkState(AbstractBlockBase<?> block, LIRInstruction op, TraceInterval[] inputState, Value operand, Value reg, TraceInterval interval) {
204 if (reg != null && isRegister(reg)) {
205 if (inputState[asRegister(reg).number] != interval) {
206 throw new GraalError(
207 "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",
208 op, block, reg, operand, interval, inputState[asRegister(reg).number]);
209 }
210 }
211 return true;
212 }
213
214 void processOperations(AbstractBlockBase<?> block, final TraceInterval[] inputState) {
215 ArrayList<LIRInstruction> ops = allocator.getLIR().getLIRforBlock(block);
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 (isVariableOrRegister(operand) && allocator.isProcessed(operand) && op.id() != TraceLinearScanPhase.DOMINATOR_SPILL_MOVE_ID) {
222 TraceInterval interval = intervalAt(asVariable(operand));
223 if (op.id() != -1) {
224 interval = interval.getSplitChildAtOpId(op.id(), mode);
225 }
226
227 assert checkState(block, op, inputState, allocator.getOperand(interval), interval.location(), interval.splitParent());
228 }
229 }
230 };
231
232 InstructionValueConsumer defConsumer = (op, operand, mode, flags) -> {
233 if (isVariableOrRegister(operand) && allocator.isProcessed(operand)) {
234 TraceInterval interval = intervalAt(asVariable(operand));
235 if (op.id() != -1) {
236 interval = interval.getSplitChildAtOpId(op.id(), mode);
237 }
238
239 statePut(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(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 }