lib/Target/XCore/XCoreMachineFunctionInfo.cpp

   1 //===-- XCoreMachineFunctionInfo.cpp - XCore machine function info --------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "XCoreMachineFunctionInfo.h"
  10 #include "XCoreInstrInfo.h"
  11 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  12 #include "llvm/IR/Function.h"
  13
  14 using namespace llvm;
  15
  16 void XCoreFunctionInfo::anchor() { }
  17
  18 bool XCoreFunctionInfo::isLargeFrame(const MachineFunction &MF) const {
  19   if (CachedEStackSize == -1) {
  20     CachedEStackSize = MF.getFrameInfo().estimateStackSize(MF);
  21   }
  22   // isLargeFrame() is used when deciding if spill slots should be added to
  23   // allow eliminateFrameIndex() to scavenge registers.
  24   // This is only required when there is no FP and offsets are greater than
  25   // ~256KB (~64Kwords). Thus only for code run on the emulator!
  26   //
  27   // The arbitrary value of 0xf000 allows frames of up to ~240KB before spill
  28   // slots are added for the use of eliminateFrameIndex() register scavenging.
  29   // For frames less than 240KB, it is assumed that there will be less than
  30   // 16KB of function arguments.
  31   return CachedEStackSize > 0xf000;
  32 }
  33
  34 int XCoreFunctionInfo::createLRSpillSlot(MachineFunction &MF) {
  35   if (LRSpillSlotSet) {
  36     return LRSpillSlot;
  37   }
  38   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  39   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  40   MachineFrameInfo &MFI = MF.getFrameInfo();
  41   if (! MF.getFunction().isVarArg()) {
  42     // A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
  43     LRSpillSlot = MFI.CreateFixedObject(TRI.getSpillSize(RC), 0, true);
  44   } else {
  45     LRSpillSlot = MFI.CreateStackObject(TRI.getSpillSize(RC),
  46                                         TRI.getSpillAlignment(RC), true);
  47   }
  48   LRSpillSlotSet = true;
  49   return LRSpillSlot;
  50 }
  51
  52 int XCoreFunctionInfo::createFPSpillSlot(MachineFunction &MF) {
  53   if (FPSpillSlotSet) {
  54     return FPSpillSlot;
  55   }
  56   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  57   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  58   MachineFrameInfo &MFI = MF.getFrameInfo();
  59   FPSpillSlot = MFI.CreateStackObject(TRI.getSpillSize(RC),
  60                                       TRI.getSpillAlignment(RC), true);
  61   FPSpillSlotSet = true;
  62   return FPSpillSlot;
  63 }
  64
  65 const int* XCoreFunctionInfo::createEHSpillSlot(MachineFunction &MF) {
  66   if (EHSpillSlotSet) {
  67     return EHSpillSlot;
  68   }
  69   const TargetRegisterClass &RC = XCore::GRRegsRegClass;
  70   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
  71   MachineFrameInfo &MFI = MF.getFrameInfo();
  72   unsigned Size = TRI.getSpillSize(RC);
  73   unsigned Align = TRI.getSpillAlignment(RC);
  74   EHSpillSlot[0] = MFI.CreateStackObject(Size, Align, true);
  75   EHSpillSlot[1] = MFI.CreateStackObject(Size, Align, true);
  76   EHSpillSlotSet = true;
  77   return EHSpillSlot;
  78 }
  79