lib/Target/XCore/XCoreMachineFunctionInfo.cpp

   1 //===-- XCoreMachineFunctionInfo.cpp - XCore machine function info --------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "XCoreMachineFunctionInfo.h"
  11 #include "XCoreInstrInfo.h"
  12 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  13 #include "llvm/IR/Function.h"
  14
  15 using namespace llvm;
  16
  17 void XCoreFunctionInfo::anchor() { }
  18
  19 bool XCoreFunctionInfo::isLargeFrame(const MachineFunction &MF) const {
  20   if (CachedEStackSize == -1) {
  21     CachedEStackSize = MF.getFrameInfo().estimateStackSize(MF);
  22   }
  23   // isLargeFrame() is used when deciding if spill slots should be added to
  24   // allow eliminateFrameIndex() to scavenge registers.
  25   // This is only required when there is no FP and offsets are greater than
  26   // ~256KB (~64Kwords). Thus only for code run on the emulator!
  27   //
  28   // The arbitrary value of 0xf000 allows frames of up to ~240KB before spill
  29   // slots are added for the use of eliminateFrameIndex() register scavenging.
  30   // For frames less than 240KB, it is assumed that there will be less than
  31   // 16KB of function arguments.
  32   return CachedEStackSize > 0xf000;
  33 }
  34
  35 int XCoreFunctionInfo::createLRSpillSlot(MachineFunction &MF) {
  36   if (LRSpillSlotSet) {
  37     return LRSpillSlot;
  38   }
  39   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  40   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  41   MachineFrameInfo &MFI = MF.getFrameInfo();
  42   if (! MF.getFunction().isVarArg()) {
  43     // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
  44     LRSpillSlot = MFI.CreateFixedObject(TRI.getSpillSize(RC), 0, true);
  45   } else {
  46     LRSpillSlot = MFI.CreateStackObject(TRI.getSpillSize(RC),
  47                                         TRI.getSpillAlignment(RC), true);
  48   }
  49   LRSpillSlotSet = true;
  50   return LRSpillSlot;
  51 }
  52
  53 int XCoreFunctionInfo::createFPSpillSlot(MachineFunction &MF) {
  54   if (FPSpillSlotSet) {
  55     return FPSpillSlot;
  56   }
  57   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  58   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  59   MachineFrameInfo &MFI = MF.getFrameInfo();
  60   FPSpillSlot = MFI.CreateStackObject(TRI.getSpillSize(RC),
  61                                       TRI.getSpillAlignment(RC), true);
  62   FPSpillSlotSet = true;
  63   return FPSpillSlot;
  64 }
  65
  66 const int* XCoreFunctionInfo::createEHSpillSlot(MachineFunction &MF) {
  67   if (EHSpillSlotSet) {
  68     return EHSpillSlot;
  69   }
  70   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  71   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  72   MachineFrameInfo &MFI = MF.getFrameInfo();
  73   unsigned Size = TRI.getSpillSize(RC);
  74   unsigned Align = TRI.getSpillAlignment(RC);
  75   EHSpillSlot[0] = MFI.CreateStackObject(Size, Align, true);
  76   EHSpillSlot[1] = MFI.CreateStackObject(Size, Align, true);
  77   EHSpillSlotSet = true;
  78   return EHSpillSlot;
  79 }
  80