C++ LabelInstruction类代码示例

void LinearScan::collectNativesAux(Trace* trace) {
  for (IRInstruction* inst : trace->getInstructionList()) {
    if (inst->isNative()) {
      m_natives.push_back(inst);
    }
    if (inst->isControlFlowInstruction()) {
      LabelInstruction* label = inst->getLabel();
      if (label != NULL && label->getId() == inst->getId() + 1) {
        collectNativesAux(label->getParent());
      }
    }
  }
}

void LinearScan::allocRegsToTraceAux(Trace* trace) {
  IRInstruction::List& instructionList = trace->getInstructionList();
  IRInstruction::Iterator it;
  for (it = instructionList.begin();
       it != instructionList.end();
       it++) {
    IRInstruction* inst = *it;
    allocRegToInstruction(trace, it);
    if (RuntimeOption::EvalDumpIR > 3) {
      std::cout << "--- allocated to instruction: ";
      inst->print(std::cout);
      std::cout << "\n";
    }
    if (inst->isControlFlowInstruction()) {
      // This instruction may transfer control to another trace
      // If this is the last instruction in the trace that can branch
      // to this target trace, then allocate registers to the target
      // trace, effectively linearizing the target trace after inst.
      LabelInstruction* label = inst->getLabel();
      if (label != NULL && label->getId() == inst->getId() + 1) {
        allocRegsToTraceAux(label->getTrace());
      }
    }
  }

  // Insert spill instructions.
  // Reload instructions are already added in <allocRegsToTrace>.
  for (it = instructionList.begin(); it != instructionList.end(); ) {
    IRInstruction::Iterator next = it; ++next;
    IRInstruction* inst = *it;
    if (inst->getOpcode() != Reload) {
      // Reloaded SSATmps needn't be spilled again.
      if (SSATmp* dst = inst->getDst()) {
        int32 slotId = dst->getSpillSlot();
        if (slotId != -1) {
          // If this instruction is marked to be spilled,
          // add a spill right afterwards.
          IRInstruction* spillInst =
            m_slots[slotId].m_slotTmp->getInstruction();
          instructionList.insert(next, spillInst);
          spillInst->setParent(trace);
        }
      }
    }
    it = next;
  }
}

void LinearScan::collectNativesAux(Trace* trace) {
  IRInstruction::List& instList = trace->getInstructionList();
  for (IRInstruction::Iterator it = instList.begin();
       it != instList.end();
       ++it) {
    IRInstruction* inst = *it;
    if (inst->isNative()) {
      m_natives.push_back(inst);
    }
    if (inst->isControlFlowInstruction()) {
      LabelInstruction* label = inst->getLabel();
      if (label != NULL && label->getId() == inst->getId() + 1) {
        collectNativesAux(label->getTrace());
      }
    }
  }
}

// If main trace starts with guards, have them generate a patchable jump
// to the anchor trace
static void hoistGuardJumps(Trace* trace, IRFactory* irFactory) {
  LabelInstruction* guardLabel = nullptr;
  IRInstruction::List& instList = trace->getInstructionList();
  // Check the beginning of the trace for guards
  for (IRInstruction* inst : instList) {
    Opcode opc = inst->getOpcode();
    if (inst->getLabel() &&
        (opc == LdLoc    || opc == LdStack ||
         opc == GuardLoc || opc == GuardStk)) {
      LabelInstruction* exitLabel = inst->getLabel();
      // Find the GuardFailure's label and confirm this branches there
      if (!guardLabel && exitLabel->getParent() != trace) {
        Trace* exitTrace = exitLabel->getParent();
        IRInstruction::List& xList = exitTrace->getInstructionList();
        IRInstruction::Iterator instIter = xList.begin();
        instIter++; // skip over label
        // Confirm this is a GuardExit
        for (IRInstruction::Iterator it = instIter; it != xList.end(); ++it) {
          IRInstruction* i = *it;
          Opcode op = i->getOpcode();
          if (op == Marker) {
            continue;
          }
          if (op == ExitGuardFailure) {
            guardLabel = exitLabel;
          }
          // Do not optimize if other instructions are on exit trace
          break;
        }
      }
      if (exitLabel == guardLabel) {
        inst->setTCA(kIRDirectGuardActive);
        continue;
      }
      break;
    }
    if (opc == Marker || opc == DefLabel || opc == DefSP || opc == DefFP ||
        opc == LdStack) {
      continue;
    }
    break;
  }
}

void LinearScan::rematerializeAux(Trace* trace,
                                  SSATmp* curSp,
                                  SSATmp* curFp,
                                  std::vector<SSATmp*> localValues) {
  IRInstruction::List& instList = trace->getInstructionList();
  for (IRInstruction::Iterator it = instList.begin();
       it != instList.end();
       ++it) {
    IRInstruction* inst = *it;
    Opcode opc = inst->getOpcode();
    SSATmp* dst = inst->getDst();
    if (opc == DefFP || opc == FreeActRec) {
      curFp = dst;
      ASSERT(dst && dst->getReg() == rVmFp);
    }
    if (opc == Reload) {
      // s = Spill t0
      // t = Reload s
      SSATmp* spilledTmp = getSpilledTmp(dst);
      IRInstruction* spilledInst = spilledTmp->getInstruction();
      IRInstruction* newInst = NULL;
      if (spilledInst->isRematerializable() ||
          (spilledInst->getOpcode() == LdStack &&
           spilledInst->getSrc(0) == curSp)) {
        // XXX: could change <newInst> to the non-check version.
        // Rematerialize those rematerializable instructions (i.e.,
        // isRematerializable returns true) and LdStack.
        newInst = spilledInst->clone(m_irFactory);
        // The new instruction needn't have an exit label, because it is always
        // dominated by the original instruction.
        newInst->setLabel(NULL);
      } else {
        // Rematerialize LdLoc.
        std::vector<SSATmp*>::iterator pos =
          std::find(localValues.begin(),
                    localValues.end(),
                    canonicalize(spilledTmp));
        // Search for a local that stores the value of <spilledTmp>.
        if (pos != localValues.end()) {
          size_t locId = pos - localValues.begin();
          ASSERT(curFp != NULL);
          ConstInstruction constInst(curFp, Local(locId));
          IRInstruction* ldHomeInst =
            m_irFactory->cloneInstruction(&constInst);
          newInst = m_irFactory->ldLoc(m_irFactory->getSSATmp(ldHomeInst),
                                       dst->getType(),
                                       NULL);
        }
      }
      if (newInst) {
        newInst->setDst(dst);
        newInst->getDst()->setInstruction(newInst);
        *it = newInst;
        newInst->setParent(trace);
      }
    }

    // Updating <curSp> and <localValues>.
    if (dst && dst->getReg() == rVmSp) {
      // <inst> modifies the stack pointer.
      curSp = dst;
    }
    if (opc == LdLoc || opc == StLoc || opc == StLocNT) {
      // dst = LdLoc home
      // StLoc/StLocNT home, src
      int locId = getLocalIdFromHomeOpnd(inst->getSrc(0));
      SSATmp* localValue = (opc == LdLoc ? dst : inst->getSrc(1));
      if (int(localValues.size()) < locId + 1) {
        localValues.resize(locId + 1);
      }
      localValues[locId] = canonicalize(localValue);
    }

    if (inst->isControlFlowInstruction()) {
      LabelInstruction* label = inst->getLabel();
      if (label != NULL && label->getId() == inst->getId() + 1) {
        rematerializeAux(label->getTrace(), curSp, curFp, localValues);
      }
    }
  }
}

//.........这里部分代码省略.........
        exitInst = *tail;
        continue;
      }
      if (opc == Marker) {
        continue;
      }
      if (jccCanBeDirectExit(opc)) {
        jccInst = inst;
        break;
      }
      break;
    }
    if (jccCanBeDirectExit(opc)) {
      SSATmp* dst = jccInst->getDst();
      Trace* targetTrace = jccInst->getLabel()->getTrace();
      IRInstruction::List& targetInstList = targetTrace->getInstructionList();
      IRInstruction::Iterator targetInstIter = targetInstList.begin();
      targetInstIter++; // skip over label

      // Check for a NormalCc exit with no side effects
      for (IRInstruction::Iterator it = targetInstIter;
           it != targetInstList.end();
           ++it) {
        IRInstruction* instr = (*it);
        // Extend to support ExitSlow, ExitSlowNoProgress, ...
        Opcode opc = instr->getOpcode();
        if (opc == ExitTraceCc) {
          exitCcInst = instr;
          break;
        } else if (opc == Marker) {
          continue;
        } else {
          // Do not optimize if there are other instructions
          break;
        }
      }

      if (exitInst && exitCcInst &&
          exitCcInst->getNumSrcs() > NUM_FIXED_SRCS &&
          exitInst->getNumSrcs() > NUM_FIXED_SRCS) {
        // Found both exits, link them to Jcc for codegen
        ASSERT(dst);
        ExtendedInstruction* exCcInst = (ExtendedInstruction*)exitCcInst;
        exCcInst->appendExtendedSrc(*irFactory, dst);
        ExtendedInstruction* exInst = (ExtendedInstruction*)exitInst;
        exInst->appendExtendedSrc(*irFactory, dst);
        // Set flag so Jcc and exits know this is active
        dst->setTCA(kIRDirectJccJmpActive);
      }
    }
  }

  // If main trace starts with guards, have them generate a patchable jump
  // to the anchor trace
  if (RuntimeOption::EvalHHIRDirectExit) {
    LabelInstruction* guardLabel = NULL;
    IRInstruction::List& instList = trace->getInstructionList();
    // Check the beginning of the trace for guards
    for (IRInstruction::Iterator it = instList.begin(); it != instList.end();
         ++it) {
      IRInstruction* inst = *it;
      Opcode opc = inst->getOpcode();
      if (inst->getLabel() &&
          (opc == LdLoc    || opc == LdStack ||
           opc == GuardLoc || opc == GuardStk)) {
        LabelInstruction* exitLabel = inst->getLabel();
        // Find the GuardFailure's label and confirm this branches there
        if (guardLabel == NULL) {
          Trace* exitTrace = exitLabel->getTrace();
          IRInstruction::List& xList = exitTrace->getInstructionList();
          IRInstruction::Iterator instIter = xList.begin();
          instIter++; // skip over label
          // Confirm this is a GuardExit
          for (IRInstruction::Iterator it = instIter; it != xList.end(); ++it) {
            IRInstruction* i = *it;
            Opcode op = i->getOpcode();
            if (op == Marker) {
              continue;
            }
            if (op == ExitGuardFailure) {
              guardLabel = exitLabel;
            }
            // Do not optimize if other instructions are on exit trace
            break;
          }
        }
        if (exitLabel == guardLabel) {
          inst->setTCA(kIRDirectGuardActive);
          continue;
        }
        break;
      }
      if (opc == Marker || opc == DefLabel || opc == DefSP || opc == DefFP ||
          opc == LdStack) {
        continue;
      }
      break;
    }
  }
}

void LinearScan::rematerializeAux(Trace* trace,
                                  SSATmp* curSp,
                                  SSATmp* curFp,
                                  std::vector<SSATmp*> localValues) {
  IRInstruction::List& instList = trace->getInstructionList();
  for (IRInstruction::Iterator it = instList.begin();
       it != instList.end();
       ++it) {
    IRInstruction* inst = *it;
    Opcode opc = inst->getOpcode();
    SSATmp* dst = inst->getDst();
    if (opc == DefFP || opc == FreeActRec) {
      curFp = dst;
      assert(dst && dst->getReg() == rVmFp);
    }
    if (opc == Reload) {
      // s = Spill t0
      // t = Reload s
      SSATmp* spilledTmp = getSpilledTmp(dst);
      IRInstruction* spilledInst = spilledTmp->getInstruction();
      IRInstruction* newInst = NULL;
      if (spilledInst->isRematerializable() ||
          (spilledInst->getOpcode() == LdStack &&
           spilledInst->getSrc(0) == curSp)) {
        // XXX: could change <newInst> to the non-check version.
        // Rematerialize those rematerializable instructions (i.e.,
        // isRematerializable returns true) and LdStack.
        newInst = spilledInst->clone(m_irFactory);
        // The new instruction needn't have an exit label, because it is always
        // dominated by the original instruction.
        newInst->setLabel(NULL);
      } else {
        // Rematerialize LdLoc.
        std::vector<SSATmp*>::iterator pos =
          std::find(localValues.begin(),
                    localValues.end(),
                    canonicalize(spilledTmp));
        // Search for a local that stores the value of <spilledTmp>.
        if (pos != localValues.end()) {
          size_t locId = pos - localValues.begin();
          assert(curFp != NULL);
          ConstInstruction constInst(curFp, Local(locId));
          IRInstruction* ldHomeInst =
            m_irFactory->cloneInstruction(&constInst);
          newInst = m_irFactory->gen(LdLoc,
                                     dst->getType(),
                                     m_irFactory->getSSATmp(ldHomeInst));
        }
      }
      if (newInst) {
        UNUSED Type::Tag oldType = dst->getType();
        newInst->setDst(dst);
        dst->setInstruction(newInst);
        assert(outputType(newInst) == oldType);
        *it = newInst;
        newInst->setParent(trace);
      }
    }

    // Updating <curSp> and <localValues>.
    if (dst && dst->getReg() == rVmSp) {
      // <inst> modifies the stack pointer.
      curSp = dst;
    }
    if (opc == LdLoc || opc == StLoc || opc == StLocNT) {
      // dst = LdLoc home
      // StLoc/StLocNT home, src
      int locId = getLocalIdFromHomeOpnd(inst->getSrc(0));
      // Note that when we implement inlining, we will need to deal
      // with the new local id space of the inlined function.
      SSATmp* localValue = (opc == LdLoc ? dst : inst->getSrc(1));
      if (int(localValues.size()) < locId + 1) {
        localValues.resize(locId + 1);
      }
      localValues[locId] = canonicalize(localValue);
    }
    // Other instructions that may have side effects on locals must
    // kill the local variable values.
    else if (opc == IterInit) {
      int valLocId = inst->getSrc(3)->getConstValAsInt();
      localValues[valLocId] = NULL;
      if (inst->getNumSrcs() == 5) {
        int keyLocId = inst->getSrc(4)->getConstValAsInt();
        localValues[keyLocId] = NULL;
      }
    } else if (opc == IterNext) {
      int valLocId = inst->getSrc(2)->getConstValAsInt();
      localValues[valLocId] = NULL;
      if (inst->getNumSrcs() == 4) {
        int keyLocId = inst->getSrc(3)->getConstValAsInt();
        localValues[keyLocId] = NULL;
      }
    }

    if (inst->isControlFlowInstruction()) {
      LabelInstruction* label = inst->getLabel();
      if (label != NULL && label->getId() == inst->getId() + 1) {
        rematerializeAux(label->getParent(), curSp, curFp, localValues);
      }
    }
//.........这里部分代码省略.........