michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "jit/RegisterAllocator.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace js::jit;
michael@0: 
michael@0: bool
michael@0: AllocationIntegrityState::record()
michael@0: {
michael@0:     // Ignore repeated record() calls.
michael@0:     if (!instructions.empty())
michael@0:         return true;
michael@0: 
michael@0:     if (!instructions.appendN(InstructionInfo(), graph.numInstructions()))
michael@0:         return false;
michael@0: 
michael@0:     if (!virtualRegisters.appendN((LDefinition *)nullptr, graph.numVirtualRegisters()))
michael@0:         return false;
michael@0: 
michael@0:     if (!blocks.reserve(graph.numBlocks()))
michael@0:         return false;
michael@0:     for (size_t i = 0; i < graph.numBlocks(); i++) {
michael@0:         blocks.infallibleAppend(BlockInfo());
michael@0:         LBlock *block = graph.getBlock(i);
michael@0:         JS_ASSERT(block->mir()->id() == i);
michael@0: 
michael@0:         BlockInfo &blockInfo = blocks[i];
michael@0:         if (!blockInfo.phis.reserve(block->numPhis()))
michael@0:             return false;
michael@0: 
michael@0:         for (size_t j = 0; j < block->numPhis(); j++) {
michael@0:             blockInfo.phis.infallibleAppend(InstructionInfo());
michael@0:             InstructionInfo &info = blockInfo.phis[j];
michael@0:             LPhi *phi = block->getPhi(j);
michael@0:             JS_ASSERT(phi->numDefs() == 1);
michael@0:             uint32_t vreg = phi->getDef(0)->virtualRegister();
michael@0:             virtualRegisters[vreg] = phi->getDef(0);
michael@0:             if (!info.outputs.append(*phi->getDef(0)))
michael@0:                 return false;
michael@0:             for (size_t k = 0, kend = phi->numOperands(); k < kend; k++) {
michael@0:                 if (!info.inputs.append(*phi->getOperand(k)))
michael@0:                     return false;
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
michael@0:             LInstruction *ins = *iter;
michael@0:             InstructionInfo &info = instructions[ins->id()];
michael@0: 
michael@0:             for (size_t k = 0; k < ins->numTemps(); k++) {
michael@0:                 uint32_t vreg = ins->getTemp(k)->virtualRegister();
michael@0:                 virtualRegisters[vreg] = ins->getTemp(k);
michael@0:                 if (!info.temps.append(*ins->getTemp(k)))
michael@0:                     return false;
michael@0:             }
michael@0:             for (size_t k = 0; k < ins->numDefs(); k++) {
michael@0:                 uint32_t vreg = ins->getDef(k)->virtualRegister();
michael@0:                 virtualRegisters[vreg] = ins->getDef(k);
michael@0:                 if (!info.outputs.append(*ins->getDef(k)))
michael@0:                     return false;
michael@0:             }
michael@0:             for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
michael@0:                 if (!info.inputs.append(**alloc))
michael@0:                     return false;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return seen.init();
michael@0: }
michael@0: 
michael@0: bool
michael@0: AllocationIntegrityState::check(bool populateSafepoints)
michael@0: {
michael@0:     JS_ASSERT(!instructions.empty());
michael@0: 
michael@0: #ifdef DEBUG
michael@0:     if (IonSpewEnabled(IonSpew_RegAlloc))
michael@0:         dump();
michael@0: 
michael@0:     for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
michael@0:         LBlock *block = graph.getBlock(blockIndex);
michael@0: 
michael@0:         // Check that all instruction inputs and outputs have been assigned an allocation.
michael@0:         for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
michael@0:             LInstruction *ins = *iter;
michael@0: 
michael@0:             for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next())
michael@0:                 JS_ASSERT(!alloc->isUse());
michael@0: 
michael@0:             for (size_t i = 0; i < ins->numDefs(); i++) {
michael@0:                 LDefinition *def = ins->getDef(i);
michael@0:                 JS_ASSERT_IF(def->policy() != LDefinition::PASSTHROUGH, !def->output()->isUse());
michael@0: 
michael@0:                 LDefinition oldDef = instructions[ins->id()].outputs[i];
michael@0:                 JS_ASSERT_IF(oldDef.policy() == LDefinition::MUST_REUSE_INPUT,
michael@0:                              *def->output() == *ins->getOperand(oldDef.getReusedInput()));
michael@0:             }
michael@0: 
michael@0:             for (size_t i = 0; i < ins->numTemps(); i++) {
michael@0:                 LDefinition *temp = ins->getTemp(i);
michael@0:                 JS_ASSERT_IF(!temp->isBogusTemp(), temp->output()->isRegister());
michael@0: 
michael@0:                 LDefinition oldTemp = instructions[ins->id()].temps[i];
michael@0:                 JS_ASSERT_IF(oldTemp.policy() == LDefinition::MUST_REUSE_INPUT,
michael@0:                              *temp->output() == *ins->getOperand(oldTemp.getReusedInput()));
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: #endif
michael@0: 
michael@0:     // Check that the register assignment and move groups preserve the original
michael@0:     // semantics of the virtual registers. Each virtual register has a single
michael@0:     // write (owing to the SSA representation), but the allocation may move the
michael@0:     // written value around between registers and memory locations along
michael@0:     // different paths through the script.
michael@0:     //
michael@0:     // For each use of an allocation, follow the physical value which is read
michael@0:     // backward through the script, along all paths to the value's virtual
michael@0:     // register's definition.
michael@0:     for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
michael@0:         LBlock *block = graph.getBlock(blockIndex);
michael@0:         for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
michael@0:             LInstruction *ins = *iter;
michael@0:             const InstructionInfo &info = instructions[ins->id()];
michael@0: 
michael@0:             LSafepoint *safepoint = ins->safepoint();
michael@0:             if (safepoint) {
michael@0:                 for (size_t i = 0; i < ins->numTemps(); i++) {
michael@0:                     uint32_t vreg = info.temps[i].virtualRegister();
michael@0:                     LAllocation *alloc = ins->getTemp(i)->output();
michael@0:                     if (!checkSafepointAllocation(ins, vreg, *alloc, populateSafepoints))
michael@0:                         return false;
michael@0:                 }
michael@0:                 JS_ASSERT_IF(ins->isCall() && !populateSafepoints,
michael@0:                              safepoint->liveRegs().empty(true) &&
michael@0:                              safepoint->liveRegs().empty(false));
michael@0:             }
michael@0: 
michael@0:             size_t inputIndex = 0;
michael@0:             for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
michael@0:                 LAllocation oldInput = info.inputs[inputIndex++];
michael@0:                 if (!oldInput.isUse())
michael@0:                     continue;
michael@0: 
michael@0:                 uint32_t vreg = oldInput.toUse()->virtualRegister();
michael@0: 
michael@0:                 if (safepoint && !oldInput.toUse()->usedAtStart()) {
michael@0:                     if (!checkSafepointAllocation(ins, vreg, **alloc, populateSafepoints))
michael@0:                         return false;
michael@0:                 }
michael@0: 
michael@0:                 // Start checking at the previous instruction, in case this
michael@0:                 // instruction reuses its input register for an output.
michael@0:                 LInstructionReverseIterator riter = block->rbegin(ins);
michael@0:                 riter++;
michael@0:                 checkIntegrity(block, *riter, vreg, **alloc, populateSafepoints);
michael@0: 
michael@0:                 while (!worklist.empty()) {
michael@0:                     IntegrityItem item = worklist.popCopy();
michael@0:                     checkIntegrity(item.block, *item.block->rbegin(), item.vreg, item.alloc, populateSafepoints);
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: AllocationIntegrityState::checkIntegrity(LBlock *block, LInstruction *ins,
michael@0:                                          uint32_t vreg, LAllocation alloc, bool populateSafepoints)
michael@0: {
michael@0:     for (LInstructionReverseIterator iter(block->rbegin(ins)); iter != block->rend(); iter++) {
michael@0:         ins = *iter;
michael@0: 
michael@0:         // Follow values through assignments in move groups. All assignments in
michael@0:         // a move group are considered to happen simultaneously, so stop after
michael@0:         // the first matching move is found.
michael@0:         if (ins->isMoveGroup()) {
michael@0:             LMoveGroup *group = ins->toMoveGroup();
michael@0:             for (int i = group->numMoves() - 1; i >= 0; i--) {
michael@0:                 if (*group->getMove(i).to() == alloc) {
michael@0:                     alloc = *group->getMove(i).from();
michael@0:                     break;
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         const InstructionInfo &info = instructions[ins->id()];
michael@0: 
michael@0:         // Make sure the physical location being tracked is not clobbered by
michael@0:         // another instruction, and that if the originating vreg definition is
michael@0:         // found that it is writing to the tracked location.
michael@0: 
michael@0:         for (size_t i = 0; i < ins->numDefs(); i++) {
michael@0:             LDefinition *def = ins->getDef(i);
michael@0:             if (def->policy() == LDefinition::PASSTHROUGH)
michael@0:                 continue;
michael@0:             if (info.outputs[i].virtualRegister() == vreg) {
michael@0:                 JS_ASSERT(*def->output() == alloc);
michael@0: 
michael@0:                 // Found the original definition, done scanning.
michael@0:                 return true;
michael@0:             } else {
michael@0:                 JS_ASSERT(*def->output() != alloc);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         for (size_t i = 0; i < ins->numTemps(); i++) {
michael@0:             LDefinition *temp = ins->getTemp(i);
michael@0:             if (!temp->isBogusTemp())
michael@0:                 JS_ASSERT(*temp->output() != alloc);
michael@0:         }
michael@0: 
michael@0:         if (ins->safepoint()) {
michael@0:             if (!checkSafepointAllocation(ins, vreg, alloc, populateSafepoints))
michael@0:                 return false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // Phis are effectless, but change the vreg we are tracking. Check if there
michael@0:     // is one which produced this vreg. We need to follow back through the phi
michael@0:     // inputs as it is not guaranteed the register allocator filled in physical
michael@0:     // allocations for the inputs and outputs of the phis.
michael@0:     for (size_t i = 0; i < block->numPhis(); i++) {
michael@0:         const InstructionInfo &info = blocks[block->mir()->id()].phis[i];
michael@0:         LPhi *phi = block->getPhi(i);
michael@0:         if (info.outputs[0].virtualRegister() == vreg) {
michael@0:             for (size_t j = 0, jend = phi->numOperands(); j < jend; j++) {
michael@0:                 uint32_t newvreg = info.inputs[j].toUse()->virtualRegister();
michael@0:                 LBlock *predecessor = graph.getBlock(block->mir()->getPredecessor(j)->id());
michael@0:                 if (!addPredecessor(predecessor, newvreg, alloc))
michael@0:                     return false;
michael@0:             }
michael@0:             return true;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // No phi which defined the vreg we are tracking, follow back through all
michael@0:     // predecessors with the existing vreg.
michael@0:     for (size_t i = 0, iend = block->mir()->numPredecessors(); i < iend; i++) {
michael@0:         LBlock *predecessor = graph.getBlock(block->mir()->getPredecessor(i)->id());
michael@0:         if (!addPredecessor(predecessor, vreg, alloc))
michael@0:             return false;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: AllocationIntegrityState::checkSafepointAllocation(LInstruction *ins,
michael@0:                                                    uint32_t vreg, LAllocation alloc,
michael@0:                                                    bool populateSafepoints)
michael@0: {
michael@0:     LSafepoint *safepoint = ins->safepoint();
michael@0:     JS_ASSERT(safepoint);
michael@0: 
michael@0:     if (ins->isCall() && alloc.isRegister())
michael@0:         return true;
michael@0: 
michael@0:     if (alloc.isRegister()) {
michael@0:         AnyRegister reg = alloc.toRegister();
michael@0:         if (populateSafepoints)
michael@0:             safepoint->addLiveRegister(reg);
michael@0:         JS_ASSERT(safepoint->liveRegs().has(reg));
michael@0:     }
michael@0: 
michael@0:     LDefinition::Type type = virtualRegisters[vreg]
michael@0:                              ? virtualRegisters[vreg]->type()
michael@0:                              : LDefinition::GENERAL;
michael@0: 
michael@0:     switch (type) {
michael@0:       case LDefinition::OBJECT:
michael@0:         if (populateSafepoints) {
michael@0:             IonSpew(IonSpew_RegAlloc, "Safepoint object v%u i%u %s",
michael@0:                     vreg, ins->id(), alloc.toString());
michael@0:             if (!safepoint->addGcPointer(alloc))
michael@0:                 return false;
michael@0:         }
michael@0:         JS_ASSERT(safepoint->hasGcPointer(alloc));
michael@0:         break;
michael@0:       case LDefinition::SLOTS:
michael@0:         if (populateSafepoints) {
michael@0:             IonSpew(IonSpew_RegAlloc, "Safepoint slots v%u i%u %s",
michael@0:                     vreg, ins->id(), alloc.toString());
michael@0:             if (!safepoint->addSlotsOrElementsPointer(alloc))
michael@0:                 return false;
michael@0:         }
michael@0:         JS_ASSERT(safepoint->hasSlotsOrElementsPointer(alloc));
michael@0:         break;
michael@0: #ifdef JS_NUNBOX32
michael@0:       // Do not assert that safepoint information for nunbox types is complete,
michael@0:       // as if a vreg for a value's components are copied in multiple places
michael@0:       // then the safepoint information may not reflect all copies. All copies
michael@0:       // of payloads must be reflected, however, for generational GC.
michael@0:       case LDefinition::TYPE:
michael@0:         if (populateSafepoints) {
michael@0:             IonSpew(IonSpew_RegAlloc, "Safepoint type v%u i%u %s",
michael@0:                     vreg, ins->id(), alloc.toString());
michael@0:             if (!safepoint->addNunboxType(vreg, alloc))
michael@0:                 return false;
michael@0:         }
michael@0:         break;
michael@0:       case LDefinition::PAYLOAD:
michael@0:         if (populateSafepoints) {
michael@0:             IonSpew(IonSpew_RegAlloc, "Safepoint payload v%u i%u %s",
michael@0:                     vreg, ins->id(), alloc.toString());
michael@0:             if (!safepoint->addNunboxPayload(vreg, alloc))
michael@0:                 return false;
michael@0:         }
michael@0:         JS_ASSERT(safepoint->hasNunboxPayload(alloc));
michael@0:         break;
michael@0: #else
michael@0:       case LDefinition::BOX:
michael@0:         if (populateSafepoints) {
michael@0:             IonSpew(IonSpew_RegAlloc, "Safepoint boxed value v%u i%u %s",
michael@0:                     vreg, ins->id(), alloc.toString());
michael@0:             if (!safepoint->addBoxedValue(alloc))
michael@0:                 return false;
michael@0:         }
michael@0:         JS_ASSERT(safepoint->hasBoxedValue(alloc));
michael@0:         break;
michael@0: #endif
michael@0:       default:
michael@0:         break;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: AllocationIntegrityState::addPredecessor(LBlock *block, uint32_t vreg, LAllocation alloc)
michael@0: {
michael@0:     // There is no need to reanalyze if we have already seen this predecessor.
michael@0:     // We share the seen allocations across analysis of each use, as there will
michael@0:     // likely be common ground between different uses of the same vreg.
michael@0:     IntegrityItem item;
michael@0:     item.block = block;
michael@0:     item.vreg = vreg;
michael@0:     item.alloc = alloc;
michael@0:     item.index = seen.count();
michael@0: 
michael@0:     IntegrityItemSet::AddPtr p = seen.lookupForAdd(item);
michael@0:     if (p)
michael@0:         return true;
michael@0:     if (!seen.add(p, item))
michael@0:         return false;
michael@0: 
michael@0:     return worklist.append(item);
michael@0: }
michael@0: 
michael@0: void
michael@0: AllocationIntegrityState::dump()
michael@0: {
michael@0: #ifdef DEBUG
michael@0:     fprintf(stderr, "Register Allocation:\n");
michael@0: 
michael@0:     for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
michael@0:         LBlock *block = graph.getBlock(blockIndex);
michael@0:         MBasicBlock *mir = block->mir();
michael@0: 
michael@0:         fprintf(stderr, "\nBlock %lu", static_cast<unsigned long>(blockIndex));
michael@0:         for (size_t i = 0; i < mir->numSuccessors(); i++)
michael@0:             fprintf(stderr, " [successor %u]", mir->getSuccessor(i)->id());
michael@0:         fprintf(stderr, "\n");
michael@0: 
michael@0:         for (size_t i = 0; i < block->numPhis(); i++) {
michael@0:             const InstructionInfo &info = blocks[blockIndex].phis[i];
michael@0:             LPhi *phi = block->getPhi(i);
michael@0:             CodePosition output(phi->id(), CodePosition::OUTPUT);
michael@0: 
michael@0:             // Don't print the inputOf for phi nodes, since it's never used.
michael@0:             fprintf(stderr, "[,%u Phi [def v%u %s] <-",
michael@0:                     output.pos(),
michael@0:                     info.outputs[0].virtualRegister(),
michael@0:                     phi->getDef(0)->output()->toString());
michael@0:             for (size_t j = 0; j < phi->numOperands(); j++)
michael@0:                 fprintf(stderr, " %s", info.inputs[j].toString());
michael@0:             fprintf(stderr, "]\n");
michael@0:         }
michael@0: 
michael@0:         for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
michael@0:             LInstruction *ins = *iter;
michael@0:             const InstructionInfo &info = instructions[ins->id()];
michael@0: 
michael@0:             CodePosition input(ins->id(), CodePosition::INPUT);
michael@0:             CodePosition output(ins->id(), CodePosition::OUTPUT);
michael@0: 
michael@0:             fprintf(stderr, "[");
michael@0:             if (input != CodePosition::MIN)
michael@0:                 fprintf(stderr, "%u,%u ", input.pos(), output.pos());
michael@0:             fprintf(stderr, "%s]", ins->opName());
michael@0: 
michael@0:             if (ins->isMoveGroup()) {
michael@0:                 LMoveGroup *group = ins->toMoveGroup();
michael@0:                 for (int i = group->numMoves() - 1; i >= 0; i--) {
michael@0:                     // Use two printfs, as LAllocation::toString is not reentant.
michael@0:                     fprintf(stderr, " [%s", group->getMove(i).from()->toString());
michael@0:                     fprintf(stderr, " -> %s]", group->getMove(i).to()->toString());
michael@0:                 }
michael@0:                 fprintf(stderr, "\n");
michael@0:                 continue;
michael@0:             }
michael@0: 
michael@0:             for (size_t i = 0; i < ins->numTemps(); i++) {
michael@0:                 LDefinition *temp = ins->getTemp(i);
michael@0:                 if (!temp->isBogusTemp())
michael@0:                     fprintf(stderr, " [temp v%u %s]", info.temps[i].virtualRegister(),
michael@0:                            temp->output()->toString());
michael@0:             }
michael@0: 
michael@0:             for (size_t i = 0; i < ins->numDefs(); i++) {
michael@0:                 LDefinition *def = ins->getDef(i);
michael@0:                 fprintf(stderr, " [def v%u %s]", info.outputs[i].virtualRegister(),
michael@0:                        def->output()->toString());
michael@0:             }
michael@0: 
michael@0:             size_t index = 0;
michael@0:             for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
michael@0:                 fprintf(stderr, " [use %s", info.inputs[index++].toString());
michael@0:                 fprintf(stderr, " %s]", alloc->toString());
michael@0:             }
michael@0: 
michael@0:             fprintf(stderr, "\n");
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     fprintf(stderr, "\nIntermediate Allocations:\n\n");
michael@0: 
michael@0:     // Print discovered allocations at the ends of blocks, in the order they
michael@0:     // were discovered.
michael@0: 
michael@0:     Vector<IntegrityItem, 20, SystemAllocPolicy> seenOrdered;
michael@0:     seenOrdered.appendN(IntegrityItem(), seen.count());
michael@0: 
michael@0:     for (IntegrityItemSet::Enum iter(seen); !iter.empty(); iter.popFront()) {
michael@0:         IntegrityItem item = iter.front();
michael@0:         seenOrdered[item.index] = item;
michael@0:     }
michael@0: 
michael@0:     for (size_t i = 0; i < seenOrdered.length(); i++) {
michael@0:         IntegrityItem item = seenOrdered[i];
michael@0:         fprintf(stderr, "block %u reg v%u alloc %s\n",
michael@0:                item.block->mir()->id(), item.vreg, item.alloc.toString());
michael@0:     }
michael@0: 
michael@0:     fprintf(stderr, "\n");
michael@0: #endif
michael@0: }
michael@0: 
michael@0: const CodePosition CodePosition::MAX(UINT_MAX);
michael@0: const CodePosition CodePosition::MIN(0);
michael@0: 
michael@0: bool
michael@0: RegisterAllocator::init()
michael@0: {
michael@0:     if (!insData.init(mir, graph.numInstructions()))
michael@0:         return false;
michael@0: 
michael@0:     for (size_t i = 0; i < graph.numBlocks(); i++) {
michael@0:         LBlock *block = graph.getBlock(i);
michael@0:         for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++)
michael@0:             insData[*ins].init(*ins, block);
michael@0:         for (size_t j = 0; j < block->numPhis(); j++) {
michael@0:             LPhi *phi = block->getPhi(j);
michael@0:             insData[phi].init(phi, block);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: LMoveGroup *
michael@0: RegisterAllocator::getInputMoveGroup(uint32_t ins)
michael@0: {
michael@0:     InstructionData *data = &insData[ins];
michael@0:     JS_ASSERT(!data->ins()->isPhi());
michael@0:     JS_ASSERT(!data->ins()->isLabel());
michael@0: 
michael@0:     if (data->inputMoves())
michael@0:         return data->inputMoves();
michael@0: 
michael@0:     LMoveGroup *moves = LMoveGroup::New(alloc());
michael@0:     data->setInputMoves(moves);
michael@0:     data->block()->insertBefore(data->ins(), moves);
michael@0: 
michael@0:     return moves;
michael@0: }
michael@0: 
michael@0: LMoveGroup *
michael@0: RegisterAllocator::getMoveGroupAfter(uint32_t ins)
michael@0: {
michael@0:     InstructionData *data = &insData[ins];
michael@0:     JS_ASSERT(!data->ins()->isPhi());
michael@0: 
michael@0:     if (data->movesAfter())
michael@0:         return data->movesAfter();
michael@0: 
michael@0:     LMoveGroup *moves = LMoveGroup::New(alloc());
michael@0:     data->setMovesAfter(moves);
michael@0: 
michael@0:     if (data->ins()->isLabel())
michael@0:         data->block()->insertAfter(data->block()->getEntryMoveGroup(alloc()), moves);
michael@0:     else
michael@0:         data->block()->insertAfter(data->ins(), moves);
michael@0:     return moves;
michael@0: }