XCoreFrameToArgsOffsetElim.cpp revision 360784 
1//===-- XCoreFrameToArgsOffsetElim.cpp ----------------------------*- C++ -*-=//
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// Replace Pseudo FRAME_TO_ARGS_OFFSET with the appropriate real offset.
10//
11//===----------------------------------------------------------------------===//
12
13#include "XCore.h"
14#include "XCoreInstrInfo.h"
15#include "XCoreSubtarget.h"
16#include "llvm/CodeGen/MachineFrameInfo.h"
17#include "llvm/CodeGen/MachineFunctionPass.h"
18#include "llvm/CodeGen/MachineInstrBuilder.h"
19#include "llvm/Support/raw_ostream.h"
20#include "llvm/Target/TargetMachine.h"
21using namespace llvm;
22
23namespace {
24  struct XCoreFTAOElim : public MachineFunctionPass {
25    static char ID;
26    XCoreFTAOElim() : MachineFunctionPass(ID) {}
27
28    bool runOnMachineFunction(MachineFunction &Fn) override;
29    MachineFunctionProperties getRequiredProperties() const override {
30      return MachineFunctionProperties().set(
31          MachineFunctionProperties::Property::NoVRegs);
32    }
33
34    StringRef getPassName() const override {
35      return "XCore FRAME_TO_ARGS_OFFSET Elimination";
36    }
37  };
38  char XCoreFTAOElim::ID = 0;
39}
40
41/// createXCoreFrameToArgsOffsetEliminationPass - returns an instance of the
42/// Frame to args offset elimination pass
43FunctionPass *llvm::createXCoreFrameToArgsOffsetEliminationPass() {
44  return new XCoreFTAOElim();
45}
46
47bool XCoreFTAOElim::runOnMachineFunction(MachineFunction &MF) {
48  const XCoreInstrInfo &TII =
49      *static_cast<const XCoreInstrInfo *>(MF.getSubtarget().getInstrInfo());
50  unsigned StackSize = MF.getFrameInfo().getStackSize();
51  for (MachineFunction::iterator MFI = MF.begin(), E = MF.end(); MFI != E;
52       ++MFI) {
53    MachineBasicBlock &MBB = *MFI;
54    for (MachineBasicBlock::iterator MBBI = MBB.begin(), EE = MBB.end();
55         MBBI != EE; ++MBBI) {
56      if (MBBI->getOpcode() == XCore::FRAME_TO_ARGS_OFFSET) {
57        MachineInstr &OldInst = *MBBI;
58        Register Reg = OldInst.getOperand(0).getReg();
59        MBBI = TII.loadImmediate(MBB, MBBI, Reg, StackSize);
60        OldInst.eraseFromParent();
61      }
62    }
63  }
64  return true;
65}
66