lib/Target/TargetFrameLowering.cpp

   1 //===----- TargetFrameLowering.cpp - Implement target frame interface ------==//
   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 // Implements the layout of a stack frame on the target machine.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/MachineFrameInfo.h"
  15 #include "llvm/CodeGen/MachineFunction.h"
  16 #include "llvm/Target/TargetFrameLowering.h"
  17 #include "llvm/Target/TargetMachine.h"
  18 #include "llvm/Target/TargetRegisterInfo.h"
  19
  20 #include <cstdlib>
  21 using namespace llvm;
  22
  23 TargetFrameLowering::~TargetFrameLowering() {
  24 }
  25
  26 /// getInitialFrameState - Returns a list of machine moves that are assumed
  27 /// on entry to a function.
  28 void
  29 TargetFrameLowering::getInitialFrameState(std::vector<MachineMove> &Moves)
  30                                                                          const {
  31   // Default is to do nothing.
  32 }
  33
  34 /// getFrameIndexOffset - Returns the displacement from the frame register to
  35 /// the stack frame of the specified index. This is the default implementation
  36 /// which is overridden for some targets.
  37 int TargetFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
  38                                          int FI) const {
  39   const MachineFrameInfo *MFI = MF.getFrameInfo();
  40   return MFI->getObjectOffset(FI) + MFI->getStackSize() -
  41     getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
  42 }
  43
  44 int TargetFrameLowering::getFrameIndexReference(const MachineFunction &MF,
  45                                              int FI, unsigned &FrameReg) const {
  46   const TargetRegisterInfo *RI = MF.getTarget().getRegisterInfo();
  47
  48   // By default, assume all frame indices are referenced via whatever
  49   // getFrameRegister() says. The target can override this if it's doing
  50   // something different.
  51   FrameReg = RI->getFrameRegister(MF);
  52   return getFrameIndexOffset(MF, FI);
  53 }