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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 
~TargetFrameLowering()23 TargetFrameLowering::~TargetFrameLowering() {
24 }
25 
26 /// getFrameIndexOffset - Returns the displacement from the frame register to
27 /// the stack frame of the specified index. This is the default implementation
28 /// which is overridden for some targets.
getFrameIndexOffset(const MachineFunction & MF,int FI) const29 int TargetFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
30                                          int FI) const {
31   const MachineFrameInfo *MFI = MF.getFrameInfo();
32   return MFI->getObjectOffset(FI) + MFI->getStackSize() -
33     getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
34 }
35 
getFrameIndexReference(const MachineFunction & MF,int FI,unsigned & FrameReg) const36 int TargetFrameLowering::getFrameIndexReference(const MachineFunction &MF,
37                                              int FI, unsigned &FrameReg) const {
38   const TargetRegisterInfo *RI = MF.getTarget().getRegisterInfo();
39 
40   // By default, assume all frame indices are referenced via whatever
41   // getFrameRegister() says. The target can override this if it's doing
42   // something different.
43   FrameReg = RI->getFrameRegister(MF);
44   return getFrameIndexOffset(MF, FI);
45 }
46