1 /*
   2  * Copyright (c) 2013, 2016, 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.hotspot.sparc;
  24 
  25 import static jdk.vm.ci.code.ValueUtil.asRegister;
  26 import static jdk.vm.ci.code.ValueUtil.isRegister;
  27 import static jdk.vm.ci.sparc.SPARC.g0;
  28 import static jdk.vm.ci.sparc.SPARC.g5;
  29 import static jdk.vm.ci.sparc.SPARC.i0;
  30 import static jdk.vm.ci.sparc.SPARC.i7;
  31 import static jdk.vm.ci.sparc.SPARC.l0;
  32 import static jdk.vm.ci.sparc.SPARC.l7;
  33 import static jdk.vm.ci.sparc.SPARC.o0;
  34 import static jdk.vm.ci.sparc.SPARC.o7;
  35 import static jdk.vm.ci.sparc.SPARC.sp;
  36 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.BPCC;
  37 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.isGlobalRegister;
  38 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.Annul.NOT_ANNUL;
  39 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.BranchPredict.PREDICT_NOT_TAKEN;
  40 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.CC.Xcc;
  41 import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.NotEqual;
  42 import static org.graalvm.compiler.core.common.GraalOptions.ZapStackOnMethodEntry;
  43 
  44 import java.util.ArrayList;
  45 import java.util.HashSet;
  46 import java.util.Set;
  47 import java.util.concurrent.ConcurrentHashMap;
  48 
  49 import org.graalvm.compiler.asm.Assembler;
  50 import org.graalvm.compiler.asm.Label;
  51 import org.graalvm.compiler.asm.sparc.SPARCAddress;
  52 import org.graalvm.compiler.asm.sparc.SPARCAssembler;
  53 import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler;
  54 import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler.ScratchRegister;
  55 import org.graalvm.compiler.code.CompilationResult;
  56 import org.graalvm.compiler.code.DataSection;
  57 import org.graalvm.compiler.code.DataSection.Data;
  58 import org.graalvm.compiler.core.common.CompilationIdentifier;
  59 import org.graalvm.compiler.core.common.alloc.RegisterAllocationConfig;
  60 import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
  61 import org.graalvm.compiler.core.sparc.SPARCNodeMatchRules;
  62 import org.graalvm.compiler.debug.Debug;
  63 import org.graalvm.compiler.debug.DebugCounter;
  64 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
  65 import org.graalvm.compiler.hotspot.HotSpotDataBuilder;
  66 import org.graalvm.compiler.hotspot.HotSpotGraalRuntimeProvider;
  67 import org.graalvm.compiler.hotspot.HotSpotHostBackend;
  68 import org.graalvm.compiler.hotspot.HotSpotLIRGenerationResult;
  69 import org.graalvm.compiler.hotspot.meta.HotSpotForeignCallsProvider;
  70 import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
  71 import org.graalvm.compiler.hotspot.stubs.Stub;
  72 import org.graalvm.compiler.lir.InstructionValueConsumer;
  73 import org.graalvm.compiler.lir.LIR;
  74 import org.graalvm.compiler.lir.LIRFrameState;
  75 import org.graalvm.compiler.lir.LIRInstruction;
  76 import org.graalvm.compiler.lir.StandardOp.SaveRegistersOp;
  77 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  78 import org.graalvm.compiler.lir.asm.CompilationResultBuilderFactory;
  79 import org.graalvm.compiler.lir.asm.DataBuilder;
  80 import org.graalvm.compiler.lir.asm.FrameContext;
  81 import org.graalvm.compiler.lir.framemap.FrameMap;
  82 import org.graalvm.compiler.lir.framemap.FrameMapBuilder;
  83 import org.graalvm.compiler.lir.gen.LIRGenerationResult;
  84 import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
  85 import org.graalvm.compiler.lir.sparc.SPARCCall;
  86 import org.graalvm.compiler.lir.sparc.SPARCDelayedControlTransfer;
  87 import org.graalvm.compiler.lir.sparc.SPARCFrameMap;
  88 import org.graalvm.compiler.lir.sparc.SPARCFrameMapBuilder;
  89 import org.graalvm.compiler.lir.sparc.SPARCLIRInstructionMixin;
  90 import org.graalvm.compiler.lir.sparc.SPARCLIRInstructionMixin.SizeEstimate;
  91 import org.graalvm.compiler.lir.sparc.SPARCTailDelayedLIRInstruction;
  92 import org.graalvm.compiler.nodes.StructuredGraph;
  93 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  94 import org.graalvm.compiler.options.OptionValues;
  95 import org.graalvm.util.EconomicMap;
  96 import org.graalvm.util.EconomicSet;
  97 import org.graalvm.util.Equivalence;
  98 
  99 import jdk.vm.ci.code.CallingConvention;
 100 import jdk.vm.ci.code.Register;
 101 import jdk.vm.ci.code.RegisterConfig;
 102 import jdk.vm.ci.code.StackSlot;
 103 import jdk.vm.ci.hotspot.HotSpotCallingConventionType;
 104 import jdk.vm.ci.meta.JavaType;
 105 import jdk.vm.ci.meta.ResolvedJavaMethod;
 106 
 107 /**
 108  * HotSpot SPARC specific backend.
 109  */
 110 public class SPARCHotSpotBackend extends HotSpotHostBackend {
 111 
 112     private static final SizeEstimateStatistics CONSTANT_ESTIMATED_STATS = new SizeEstimateStatistics("ESTIMATE");
 113     private static final SizeEstimateStatistics CONSTANT_ACTUAL_STATS = new SizeEstimateStatistics("ACTUAL");
 114 
 115     public SPARCHotSpotBackend(GraalHotSpotVMConfig config, HotSpotGraalRuntimeProvider runtime, HotSpotProviders providers) {
 116         super(config, runtime, providers);
 117     }
 118 
 119     private static class SizeEstimateStatistics {
 120         private static final ConcurrentHashMap<String, DebugCounter> counters = new ConcurrentHashMap<>();
 121         private final String suffix;
 122 
 123         SizeEstimateStatistics(String suffix) {
 124             super();
 125             this.suffix = suffix;
 126         }
 127 
 128         public void add(Class<?> c, int count) {
 129             String name = SizeEstimateStatistics.class.getSimpleName() + "_" + c.getSimpleName() + "." + suffix;
 130             DebugCounter m = counters.computeIfAbsent(name, (n) -> Debug.counter(n));
 131             m.add(count);
 132         }
 133     }
 134 
 135     @Override
 136     public FrameMapBuilder newFrameMapBuilder(RegisterConfig registerConfig) {
 137         RegisterConfig registerConfigNonNull = registerConfig == null ? getCodeCache().getRegisterConfig() : registerConfig;
 138         return new SPARCFrameMapBuilder(newFrameMap(registerConfigNonNull), getCodeCache(), registerConfigNonNull);
 139     }
 140 
 141     @Override
 142     public FrameMap newFrameMap(RegisterConfig registerConfig) {
 143         return new SPARCFrameMap(getCodeCache(), registerConfig, this);
 144     }
 145 
 146     @Override
 147     public LIRGeneratorTool newLIRGenerator(LIRGenerationResult lirGenRes) {
 148         return new SPARCHotSpotLIRGenerator(getProviders(), getRuntime().getVMConfig(), lirGenRes);
 149     }
 150 
 151     @Override
 152     public LIRGenerationResult newLIRGenerationResult(CompilationIdentifier compilationId, LIR lir, FrameMapBuilder frameMapBuilder, StructuredGraph graph, Object stub) {
 153         return new HotSpotLIRGenerationResult(compilationId, lir, frameMapBuilder, makeCallingConvention(graph, (Stub) stub), stub);
 154     }
 155 
 156     @Override
 157     public NodeLIRBuilderTool newNodeLIRBuilder(StructuredGraph graph, LIRGeneratorTool lirGen) {
 158         return new SPARCHotSpotNodeLIRBuilder(graph, lirGen, new SPARCNodeMatchRules(lirGen));
 159     }
 160 
 161     @Override
 162     protected void bangStackWithOffset(CompilationResultBuilder crb, int bangOffset) {
 163         // Use SPARCAddress to get the final displacement including the stack bias.
 164         SPARCMacroAssembler masm = (SPARCMacroAssembler) crb.asm;
 165         SPARCAddress address = new SPARCAddress(sp, -bangOffset);
 166         if (SPARCAssembler.isSimm13(address.getDisplacement())) {
 167             masm.stx(g0, address);
 168         } else {
 169             try (ScratchRegister sc = masm.getScratchRegister()) {
 170                 Register scratch = sc.getRegister();
 171                 assert isGlobalRegister(scratch) : "Only global (g1-g7) registers are allowed if the frame was not initialized here. Got register " + scratch;
 172                 masm.setx(address.getDisplacement(), scratch, false);
 173                 masm.stx(g0, new SPARCAddress(sp, scratch));
 174             }
 175         }
 176     }
 177 
 178     public class HotSpotFrameContext implements FrameContext {
 179 
 180         final boolean isStub;
 181 
 182         HotSpotFrameContext(boolean isStub) {
 183             this.isStub = isStub;
 184         }
 185 
 186         @Override
 187         public boolean hasFrame() {
 188             return true;
 189         }
 190 
 191         @Override
 192         public void enter(CompilationResultBuilder crb) {
 193             final int frameSize = crb.frameMap.totalFrameSize();
 194             final int stackpoinerChange = -frameSize;
 195             SPARCMacroAssembler masm = (SPARCMacroAssembler) crb.asm;
 196             emitStackOverflowCheck(crb);
 197 
 198             if (SPARCAssembler.isSimm13(stackpoinerChange)) {
 199                 masm.save(sp, stackpoinerChange, sp);
 200             } else {
 201                 try (ScratchRegister sc = masm.getScratchRegister()) {
 202                     Register scratch = sc.getRegister();
 203                     assert isGlobalRegister(scratch) : "Only global registers are allowed before save. Got register " + scratch;
 204                     masm.setx(stackpoinerChange, scratch, false);
 205                     masm.save(sp, scratch, sp);
 206                 }
 207             }
 208 
 209             if (ZapStackOnMethodEntry.getValue(crb.getOptions())) {
 210                 final int slotSize = 8;
 211                 for (int i = 0; i < frameSize / slotSize; ++i) {
 212                     // 0xC1C1C1C1
 213                     masm.stx(g0, new SPARCAddress(sp, i * slotSize));
 214                 }
 215             }
 216         }
 217 
 218         @Override
 219         public void leave(CompilationResultBuilder crb) {
 220             SPARCMacroAssembler masm = (SPARCMacroAssembler) crb.asm;
 221             masm.restoreWindow();
 222         }
 223     }
 224 
 225     @Override
 226     protected Assembler createAssembler(FrameMap frameMap) {
 227         return new SPARCMacroAssembler(getTarget());
 228     }
 229 
 230     @Override
 231     public CompilationResultBuilder newCompilationResultBuilder(LIRGenerationResult lirGenRes, FrameMap frameMap, CompilationResult compilationResult, CompilationResultBuilderFactory factory) {
 232         HotSpotLIRGenerationResult gen = (HotSpotLIRGenerationResult) lirGenRes;
 233         LIR lir = gen.getLIR();
 234         assert gen.getDeoptimizationRescueSlot() == null || frameMap.frameNeedsAllocating() : "method that can deoptimize must have a frame";
 235 
 236         Stub stub = gen.getStub();
 237         Assembler masm = createAssembler(frameMap);
 238         // On SPARC we always use stack frames.
 239         HotSpotFrameContext frameContext = new HotSpotFrameContext(stub != null);
 240         DataBuilder dataBuilder = new HotSpotDataBuilder(getCodeCache().getTarget());
 241         OptionValues options = lir.getOptions();
 242         CompilationResultBuilder crb = factory.createBuilder(getProviders().getCodeCache(), getProviders().getForeignCalls(), frameMap, masm, dataBuilder, frameContext, options, compilationResult);
 243         crb.setTotalFrameSize(frameMap.totalFrameSize());
 244         crb.setMaxInterpreterFrameSize(gen.getMaxInterpreterFrameSize());
 245         StackSlot deoptimizationRescueSlot = gen.getDeoptimizationRescueSlot();
 246         if (deoptimizationRescueSlot != null && stub == null) {
 247             crb.compilationResult.setCustomStackAreaOffset(deoptimizationRescueSlot);
 248         }
 249 
 250         if (stub != null) {
 251             // Even on sparc we need to save floating point registers
 252             EconomicSet<Register> destroyedCallerRegisters = gatherDestroyedCallerRegisters(lir);
 253             EconomicMap<LIRFrameState, SaveRegistersOp> calleeSaveInfo = gen.getCalleeSaveInfo();
 254             updateStub(stub, destroyedCallerRegisters, calleeSaveInfo, frameMap);
 255         }
 256         assert registerSizePredictionValidator(crb);
 257         return crb;
 258     }
 259 
 260     /**
 261      * Registers a verifier which checks if the LIRInstructions estimate of constants size is
 262      * greater or equal to the actual one.
 263      */
 264     private static boolean registerSizePredictionValidator(final CompilationResultBuilder crb) {
 265         /**
 266          * Used to hold state between beforeOp and afterOp
 267          */
 268         class ValidationState {
 269             LIRInstruction op;
 270             int constantSizeBefore;
 271 
 272             public void before(LIRInstruction before) {
 273                 assert op == null : "LIRInstruction " + op + " no after call received";
 274                 op = before;
 275                 constantSizeBefore = calculateDataSectionSize(crb.compilationResult.getDataSection());
 276             }
 277 
 278             public void after(LIRInstruction after) {
 279                 assert after.equals(op) : "Instructions before/after don't match " + op + "/" + after;
 280                 int constantSizeAfter = calculateDataSectionSize(crb.compilationResult.getDataSection());
 281                 int actual = constantSizeAfter - constantSizeBefore;
 282                 if (op instanceof SPARCLIRInstructionMixin) {
 283                     org.graalvm.compiler.lir.sparc.SPARCLIRInstructionMixin.SizeEstimate size = ((SPARCLIRInstructionMixin) op).estimateSize();
 284                     assert size != null : "No size prediction available for op: " + op;
 285                     Class<?> c = op.getClass();
 286                     CONSTANT_ESTIMATED_STATS.add(c, size.constantSize);
 287                     CONSTANT_ACTUAL_STATS.add(c, actual);
 288                     assert size.constantSize >= actual : "Op " + op + " exceeded estimated constant size; predicted: " + size.constantSize + " actual: " + actual;
 289                 } else {
 290                     assert actual == 0 : "Op " + op + " emitted to DataSection without any estimate.";
 291                 }
 292                 op = null;
 293                 constantSizeBefore = 0;
 294             }
 295         }
 296         final ValidationState state = new ValidationState();
 297         crb.setOpCallback(op -> state.before(op), op -> state.after(op));
 298         return true;
 299     }
 300 
 301     private static int calculateDataSectionSize(DataSection ds) {
 302         int sum = 0;
 303         for (Data d : ds) {
 304             sum += d.getSize();
 305         }
 306         return sum;
 307     }
 308 
 309     @Override
 310     public void emitCode(CompilationResultBuilder crb, LIR lir, ResolvedJavaMethod installedCodeOwner) {
 311         SPARCMacroAssembler masm = (SPARCMacroAssembler) crb.asm;
 312         // TODO: (sa) Fold the two traversals into one
 313         stuffDelayedControlTransfers(lir);
 314         int constantSize = calculateConstantSize(lir);
 315         boolean canUseImmediateConstantLoad = constantSize < (1 << 13);
 316         masm.setImmediateConstantLoad(canUseImmediateConstantLoad);
 317         FrameMap frameMap = crb.frameMap;
 318         RegisterConfig regConfig = frameMap.getRegisterConfig();
 319         Label unverifiedStub = installedCodeOwner == null || installedCodeOwner.isStatic() ? null : new Label();
 320         for (int i = 0; i < 2; i++) {
 321             if (i > 0) {
 322                 crb.resetForEmittingCode();
 323                 lir.resetLabels();
 324                 resetDelayedControlTransfers(lir);
 325             }
 326 
 327             // Emit the prefix
 328             if (unverifiedStub != null) {
 329                 crb.recordMark(config.MARKID_UNVERIFIED_ENTRY);
 330                 // We need to use JavaCall here because we haven't entered the frame yet.
 331                 CallingConvention cc = regConfig.getCallingConvention(HotSpotCallingConventionType.JavaCall, null, new JavaType[]{getProviders().getMetaAccess().lookupJavaType(Object.class)}, this);
 332                 Register inlineCacheKlass = g5; // see MacroAssembler::ic_call
 333 
 334                 try (ScratchRegister sc = masm.getScratchRegister()) {
 335                     Register scratch = sc.getRegister();
 336                     Register receiver = asRegister(cc.getArgument(0));
 337                     SPARCAddress src = new SPARCAddress(receiver, config.hubOffset);
 338 
 339                     masm.ldx(src, scratch);
 340                     masm.cmp(scratch, inlineCacheKlass);
 341                 }
 342                 BPCC.emit(masm, Xcc, NotEqual, NOT_ANNUL, PREDICT_NOT_TAKEN, unverifiedStub);
 343                 masm.nop();  // delay slot
 344             }
 345 
 346             masm.align(config.codeEntryAlignment);
 347             crb.recordMark(config.MARKID_OSR_ENTRY);
 348             crb.recordMark(config.MARKID_VERIFIED_ENTRY);
 349 
 350             // Emit code for the LIR
 351             crb.emit(lir);
 352         }
 353         profileInstructions(lir, crb);
 354 
 355         HotSpotFrameContext frameContext = (HotSpotFrameContext) crb.frameContext;
 356         HotSpotForeignCallsProvider foreignCalls = getProviders().getForeignCalls();
 357         if (!frameContext.isStub) {
 358             crb.recordMark(config.MARKID_EXCEPTION_HANDLER_ENTRY);
 359             SPARCCall.directCall(crb, masm, foreignCalls.lookupForeignCall(EXCEPTION_HANDLER), null, null);
 360             crb.recordMark(config.MARKID_DEOPT_HANDLER_ENTRY);
 361             SPARCCall.directCall(crb, masm, foreignCalls.lookupForeignCall(DEOPTIMIZATION_HANDLER), null, null);
 362         } else {
 363             // No need to emit the stubs for entries back into the method since
 364             // it has no calls that can cause such "return" entries
 365         }
 366 
 367         if (unverifiedStub != null) {
 368             masm.bind(unverifiedStub);
 369             try (ScratchRegister sc = masm.getScratchRegister()) {
 370                 Register scratch = sc.getRegister();
 371                 SPARCCall.indirectJmp(crb, masm, scratch, foreignCalls.lookupForeignCall(IC_MISS_HANDLER));
 372             }
 373         }
 374         masm.peephole();
 375     }
 376 
 377     private static int calculateConstantSize(LIR lir) {
 378         int size = 0;
 379         for (AbstractBlockBase<?> block : lir.codeEmittingOrder()) {
 380             if (block == null) {
 381                 continue;
 382             }
 383             for (LIRInstruction inst : lir.getLIRforBlock(block)) {
 384                 if (inst instanceof SPARCLIRInstructionMixin) {
 385                     SizeEstimate pred = ((SPARCLIRInstructionMixin) inst).estimateSize();
 386                     if (pred != null) {
 387                         size += pred.constantSize;
 388                     }
 389                 }
 390             }
 391         }
 392         return size;
 393     }
 394 
 395     private static void resetDelayedControlTransfers(LIR lir) {
 396         for (AbstractBlockBase<?> block : lir.codeEmittingOrder()) {
 397             if (block == null) {
 398                 continue;
 399             }
 400             for (LIRInstruction inst : lir.getLIRforBlock(block)) {
 401                 if (inst instanceof SPARCDelayedControlTransfer) {
 402                     ((SPARCDelayedControlTransfer) inst).resetState();
 403                 }
 404             }
 405         }
 406     }
 407 
 408     /**
 409      * Fix-up over whole LIR.
 410      *
 411      * @see #stuffDelayedControlTransfers(LIR, AbstractBlockBase)
 412      * @param l
 413      */
 414     private static void stuffDelayedControlTransfers(LIR l) {
 415         for (AbstractBlockBase<?> b : l.codeEmittingOrder()) {
 416             if (b != null) {
 417                 stuffDelayedControlTransfers(l, b);
 418             }
 419         }
 420     }
 421 
 422     /**
 423      * Tries to put DelayedControlTransfer instructions and DelayableLIRInstructions together. Also
 424      * it tries to move the DelayedLIRInstruction to the DelayedControlTransfer instruction, if
 425      * possible.
 426      */
 427     private static void stuffDelayedControlTransfers(LIR l, AbstractBlockBase<?> block) {
 428         ArrayList<LIRInstruction> instructions = l.getLIRforBlock(block);
 429         if (instructions.size() >= 2) {
 430             LIRDependencyAccumulator acc = new LIRDependencyAccumulator();
 431             SPARCDelayedControlTransfer delayedTransfer = null;
 432             int delayTransferPosition = -1;
 433             for (int i = instructions.size() - 1; i >= 0; i--) {
 434                 LIRInstruction inst = instructions.get(i);
 435                 boolean adjacent = delayTransferPosition - i == 1;
 436                 if (!adjacent || inst.destroysCallerSavedRegisters() || leavesRegisterWindow(inst)) {
 437                     delayedTransfer = null;
 438                 }
 439                 if (inst instanceof SPARCDelayedControlTransfer) {
 440                     delayedTransfer = (SPARCDelayedControlTransfer) inst;
 441                     acc.start(inst);
 442                     delayTransferPosition = i;
 443                 } else if (delayedTransfer != null) {
 444                     boolean overlap = acc.add(inst);
 445                     if (!overlap && inst instanceof SPARCTailDelayedLIRInstruction) {
 446                         // We have found a non overlapping LIR instruction which can be delayed
 447                         ((SPARCTailDelayedLIRInstruction) inst).setDelayedControlTransfer(delayedTransfer);
 448                         delayedTransfer = null;
 449                     }
 450                 }
 451             }
 452         }
 453     }
 454 
 455     private static boolean leavesRegisterWindow(LIRInstruction inst) {
 456         return inst instanceof SPARCLIRInstructionMixin && ((SPARCLIRInstructionMixin) inst).leavesRegisterWindow();
 457     }
 458 
 459     /**
 460      * Accumulates inputs/outputs/temp/alive in a set along we walk back the LIRInstructions and
 461      * detects, if there is any overlap. In this way LIRInstructions can be detected, which can be
 462      * moved nearer to the DelayedControlTransfer instruction.
 463      */
 464     private static class LIRDependencyAccumulator {
 465         private final Set<Object> inputs = new HashSet<>(10);
 466         private boolean overlap = false;
 467 
 468         private final InstructionValueConsumer valueConsumer = (instruction, value, mode, flags) -> {
 469             Object valueObject = value;
 470             if (isRegister(value)) { // Canonicalize registers
 471                 valueObject = asRegister(value);
 472             }
 473             if (!inputs.add(valueObject)) {
 474                 overlap = true;
 475             }
 476         };
 477 
 478         public void start(LIRInstruction initial) {
 479             inputs.clear();
 480             overlap = false;
 481             initial.visitEachInput(valueConsumer);
 482             initial.visitEachTemp(valueConsumer);
 483             initial.visitEachAlive(valueConsumer);
 484         }
 485 
 486         /**
 487          * Adds the inputs of lir instruction to the accumulator and returns, true if there was any
 488          * overlap of parameters.
 489          *
 490          * @param inst
 491          * @return true if an overlap was found
 492          */
 493         public boolean add(LIRInstruction inst) {
 494             overlap = false;
 495             inst.visitEachOutput(valueConsumer);
 496             inst.visitEachTemp(valueConsumer);
 497             inst.visitEachInput(valueConsumer);
 498             inst.visitEachAlive(valueConsumer);
 499             return overlap;
 500         }
 501     }
 502 
 503     @Override
 504     public RegisterAllocationConfig newRegisterAllocationConfig(RegisterConfig registerConfig, String[] allocationRestrictedTo) {
 505         RegisterConfig registerConfigNonNull = registerConfig == null ? getCodeCache().getRegisterConfig() : registerConfig;
 506         return new SPARCHotSpotRegisterAllocationConfig(registerConfigNonNull, allocationRestrictedTo);
 507     }
 508 
 509     @Override
 510     public EconomicSet<Register> translateToCallerRegisters(EconomicSet<Register> calleeRegisters) {
 511         EconomicSet<Register> callerRegisters = EconomicSet.create(Equivalence.IDENTITY, calleeRegisters.size());
 512         for (Register register : calleeRegisters) {
 513             if (l0.number <= register.number && register.number <= l7.number) {
 514                 // do nothing
 515             } else if (o0.number <= register.number && register.number <= o7.number) {
 516                 // do nothing
 517             } else if (i0.number <= register.number && register.number <= i7.number) {
 518                 // translate input to output registers
 519                 callerRegisters.add(translateInputToOutputRegister(register));
 520             } else {
 521                 callerRegisters.add(register);
 522             }
 523         }
 524         return callerRegisters;
 525     }
 526 
 527     private Register translateInputToOutputRegister(Register register) {
 528         assert i0.number <= register.number && register.number <= i7.number : "Not an input register " + register;
 529         return getTarget().arch.getRegisters().get(o0.number + register.number - i0.number);
 530     }
 531 }