lib/Target/XCore/XCoreFrameToArgsOffsetElim.cpp

   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"
  21 using namespace llvm;
  22
  23 namespace {
  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
  43 FunctionPass *llvm::createXCoreFrameToArgsOffsetEliminationPass() {
  44   return new XCoreFTAOElim();
  45 }
  46
  47 bool 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 }