C++ Machine::coerceRegisterAssignment方法代码示例

static void assignFreeRegisters(TR::Instruction              *currentInstruction,
                                TR::RegisterDependency    *dep,
                                TR_PPCRegisterDependencyMap& map,
                                TR::CodeGenerator            *cg)
   {
   // *this    swipeable for debugging purposes
   TR::Machine *machine = cg->machine();

   // Assign a chain of dependencies where the head of the chain depends on a free reg
   while (dep)
      {
      TR_ASSERT(machine->getPPCRealRegister(dep->getRealRegister())->getState() == TR::RealRegister::Free, "Expecting free target register");
      TR::RealRegister *assignedReg = dep->getRegister()->getAssignedRealRegister() ?
         toRealRegister(dep->getRegister()->getAssignedRealRegister()) : NULL;
      machine->coerceRegisterAssignment(currentInstruction, dep->getRegister(), dep->getRealRegister());
      dep->getRegister()->block();
      dep = assignedReg ?
         map.getDependencyWithTarget(assignedReg->getRegisterNumber()) : NULL;
      }
   }

//.........这里部分代码省略.........
         {
         assignFreeRegisters(currentInstruction, &_dependencies[i], map, cg);
         }
      }

   // Assign all virtual regs that depend on a specfic real reg that is not free
   for (i = 0; i < numberOfRegisters; i++)
      {
      virtReg     = _dependencies[i].getRegister();
      assignedRegister = NULL;
      if (virtReg->getAssignedRealRegister() != NULL)
         {
         assignedRegister = toRealRegister(virtReg->getAssignedRealRegister());
         }
      dependentRegNum = _dependencies[i].getRealRegister();
      dependentRealReg = machine->getPPCRealRegister(dependentRegNum);
      if (dependentRegNum != TR::RealRegister::NoReg &&
          dependentRegNum != TR::RealRegister::SpilledReg &&
          dependentRealReg != assignedRegister)
         {
         bool depsBlocked = false;
         switch (_dependencies[i].getRegister()->getKind())
            {
            case TR_GPR:
               depsBlocked = block_gprs;
               break;
            case TR_FPR:
               depsBlocked = block_fprs;
               break;
            case TR_VRF:
               depsBlocked = block_vrfs;
               break;
            }
         assignContendedRegisters(currentInstruction, &_dependencies[i], map, depsBlocked, cg);
         }
      }

   // Assign all virtual regs that depend on NoReg but exclude gr0
   for (i=0; i<numberOfRegisters; i++)
      {
      if (_dependencies[i].getRealRegister() == TR::RealRegister::NoReg && _dependencies[i].getExcludeGPR0())
         {
         TR::RealRegister *realOne;

         virtReg     = _dependencies[i].getRegister();
         realOne     = virtReg->getAssignedRealRegister();
         if (realOne!=NULL && toRealRegister(realOne)->getRegisterNumber()==TR::RealRegister::gr0)
            {
            if ((assignedRegister = machine->findBestFreeRegister(currentInstruction, virtReg->getKind(), true, false, virtReg)) == NULL)
               {
               assignedRegister = machine->freeBestRegister(currentInstruction, virtReg, NULL, true);
               }
            machine->coerceRegisterAssignment(currentInstruction, virtReg, assignedRegister->getRegisterNumber());
            }
         else if (realOne == NULL)
            {
            machine->assignOneRegister(currentInstruction, virtReg, true);
            }
         virtReg->block();
         }
      }

   // Assign all virtual regs that depend on NoReg
   for (i=0; i<numberOfRegisters; i++)
      {
      if (_dependencies[i].getRealRegister() == TR::RealRegister::NoReg && !_dependencies[i].getExcludeGPR0())
         {
         TR::RealRegister *realOne;

         virtReg     = _dependencies[i].getRegister();
         realOne     = virtReg->getAssignedRealRegister();
         if (!realOne)
            {
            machine->assignOneRegister(currentInstruction, virtReg, false);
            }
         virtReg->block();
         }
      }

   unblockRegisters(numberOfRegisters);
   for (i = 0; i < numberOfRegisters; i++)
      {
      TR::Register     *dependentRegister = getRegisterDependency(i)->getRegister();
      // dependentRegister->getAssignedRegister() is NULL if the reg has already been spilled due to a spilledReg dep
      if (comp->getOption(TR_DisableOOL) || (!(cg->isOutOfLineColdPath()) && !(cg->isOutOfLineHotPath())))
         {
         TR_ASSERT(dependentRegister->getAssignedRegister(),
             "assignedRegister can not  be NULL");
         }
      if (dependentRegister->getAssignedRegister())
         {
         TR::RealRegister *assignedRegister = dependentRegister->getAssignedRegister()->getRealRegister();

         if (getRegisterDependency(i)->getRealRegister() == TR::RealRegister::NoReg)
            getRegisterDependency(i)->setRealRegister(toRealRegister(assignedRegister)->getRegisterNumber());

         machine->decFutureUseCountAndUnlatch(dependentRegister);
         }
      }
   }

static void assignContendedRegisters(TR::Instruction              *currentInstruction,
                                     TR::RegisterDependency    *dep,
                                     TR_PPCRegisterDependencyMap& map,
                                     bool                         depsBlocked,
                                     TR::CodeGenerator            *cg)
   {
   // *this    swipeable for debugging purposes
   TR::Machine *machine = cg->machine();

   dep = findDependencyChainHead(dep, map);


   TR::Register *virtReg = dep->getRegister();
   TR::RealRegister::RegNum targetRegNum = dep->getRealRegister();
   TR::RealRegister *targetReg = machine->getPPCRealRegister(targetRegNum);
   TR::RealRegister *assignedReg = virtReg->getAssignedRealRegister() ?
      toRealRegister(virtReg->getAssignedRealRegister()) :  NULL;


   // Chain of length 1
   if (!assignedReg || !map.getDependencyWithTarget(assignedReg->getRegisterNumber()))
      {
      machine->coerceRegisterAssignment(currentInstruction, virtReg, targetRegNum);
      virtReg->block();
      return;
      }
   // Chain of length 2, handled here instead of below to get 3*xor exchange on GPRs
   if (map.getDependencyWithTarget(assignedReg->getRegisterNumber()) == map.getDependencyWithAssigned(targetRegNum))
      {
      TR::Register *targetVirtReg = targetReg->getAssignedRegister();
      machine->coerceRegisterAssignment(currentInstruction, virtReg, targetRegNum);
      virtReg->block();
      targetVirtReg->block();
      return;
      }

   // Grab a spare reg in order to free the target of the first dep
   // At this point the first dep's target could be blocked, assigned, or NoReg
   // If it's blocked or assigned we allocate a spare and assign the target's virtual to it
   // If it's NoReg, the spare reg will be used as the first dep's actual target
   TR::RealRegister *spareReg = machine->findBestFreeRegister(currentInstruction, virtReg->getKind(),
                                                                targetRegNum == TR::RealRegister::NoReg ? dep->getExcludeGPR0() : false, false,
                                                                targetRegNum == TR::RealRegister::NoReg ? virtReg : targetReg->getAssignedRegister());
   bool                haveFreeSpare = spareReg != NULL;
   if (!spareReg)
      {
      // If the regs in this dep group are not blocked we need to make sure we don't spill a reg that's in the middle of the chain
      if (!depsBlocked)
         {
         if (targetRegNum == TR::RealRegister::NoReg)
            spareReg = machine->freeBestRegister(currentInstruction,
                                                 map.getDependencyWithTarget(assignedReg->getRegisterNumber())->getRegister(),
                                                 assignedReg, false);
         else
            spareReg = machine->freeBestRegister(currentInstruction, virtReg, targetReg, false);
         }
      else
         {
         if (targetRegNum == TR::RealRegister::NoReg)
            spareReg = machine->freeBestRegister(currentInstruction, virtReg, NULL, dep->getExcludeGPR0());
         else
            spareReg = machine->freeBestRegister(currentInstruction, targetReg->getAssignedRegister(), NULL, false);
         }
      }

   if (targetRegNum != TR::RealRegister::NoReg && spareReg != targetReg)
      {
      machine->coerceRegisterAssignment(currentInstruction, targetReg->getAssignedRegister(), spareReg->getRegisterNumber());
      }

   TR_ASSERT(targetRegNum == TR::RealRegister::NoReg ||
          targetReg->getState() == TR::RealRegister::Free, "Expecting free target register");

   if (depsBlocked || targetRegNum != TR::RealRegister::NoReg || haveFreeSpare)
      {

      machine->coerceRegisterAssignment(currentInstruction, virtReg,
                                        targetRegNum == TR::RealRegister::NoReg ?
                                        spareReg->getRegisterNumber() : targetRegNum);
      virtReg->block();
      }

   dep = map.getDependencyWithTarget(assignedReg->getRegisterNumber());
   while (dep)
      {
      virtReg = dep->getRegister();
      targetRegNum = dep->getRealRegister();
      targetReg = machine->getPPCRealRegister(targetRegNum);
      assignedReg = virtReg->getAssignedRealRegister() ?
         toRealRegister(virtReg->getAssignedRealRegister()) : NULL;

      TR_ASSERT(targetReg->getState() == TR::RealRegister::Free || targetReg == spareReg,
             "Expecting free target register or target to have been filled to free spare register");

      machine->coerceRegisterAssignment(currentInstruction, virtReg, targetRegNum);
      virtReg->block();
      dep = assignedReg ?
         map.getDependencyWithTarget(assignedReg->getRegisterNumber()) : NULL;
      }

//.........这里部分代码省略.........

//.........这里部分代码省略.........
         {
         if (dependencies[i].getRealRegister() == TR::RealRegister::NoReg)
            {
            virtReg->block();
            }
         else
            {
            dependentRegNum = toRealRegister(virtReg->getAssignedRealRegister())->getRegisterNumber();
            for (j=0; j<numberOfRegisters; j++)
               {
               if (dependentRegNum == dependencies[j].getRealRegister())
                  {
                  virtReg->block();
                  break;
                  }
               }
            }
         }
      }

   do
      {
      changed = false;
      for (i = 0; i < numberOfRegisters; i++)
         {
         virtReg = dependencies[i].getRegister();
         dependentRegNum = dependencies[i].getRealRegister();
         dependentRealReg = machine->getRealRegister(dependentRegNum);

         if (dependentRegNum != TR::RealRegister::NoReg &&
             dependentRegNum != TR::RealRegister::SpilledReg &&
             dependentRealReg->getState() == TR::RealRegister::Free)
            {
            machine->coerceRegisterAssignment(currentInstruction, virtReg, dependentRegNum);
            virtReg->block();
            changed = true;
            }
         }
      } while (changed == true);


   do
      {
      changed = false;
      for (i = 0; i < numberOfRegisters; i++)
         {
         virtReg = dependencies[i].getRegister();
         assignedRegister = NULL;
         if (virtReg->getAssignedRealRegister() != NULL)
            {
            assignedRegister = toRealRegister(virtReg->getAssignedRealRegister());
            }
         dependentRegNum = dependencies[i].getRealRegister();
         dependentRealReg = machine->getRealRegister(dependentRegNum);
         if (dependentRegNum != TR::RealRegister::NoReg &&
             dependentRegNum != TR::RealRegister::SpilledReg &&
             dependentRealReg != assignedRegister)
            {
            machine->coerceRegisterAssignment(currentInstruction, virtReg, dependentRegNum);
            virtReg->block();
            changed = true;
            }
         }
      } while (changed == true);

   for (i=0; i<numberOfRegisters; i++)