llvm/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/Target/TargetMachine.h"
  19 using namespace llvm;
  20
  21 namespace {
  22   struct XCoreFTAOElim : public MachineFunctionPass {
  23     static char ID;
  24     XCoreFTAOElim() : MachineFunctionPass(ID) {}
  25
  26     bool runOnMachineFunction(MachineFunction &Fn) override;
  27     MachineFunctionProperties getRequiredProperties() const override {
  28       return MachineFunctionProperties().set(
  29           MachineFunctionProperties::Property::NoVRegs);
  30     }
  31
  32     StringRef getPassName() const override {
  33       return "XCore FRAME_TO_ARGS_OFFSET Elimination";
  34     }
  35   };
  36   char XCoreFTAOElim::ID = 0;
  37 }
  38
  39 /// createXCoreFrameToArgsOffsetEliminationPass - returns an instance of the
  40 /// Frame to args offset elimination pass
  41 FunctionPass *llvm::createXCoreFrameToArgsOffsetEliminationPass() {
  42   return new XCoreFTAOElim();
  43 }
  44
  45 bool XCoreFTAOElim::runOnMachineFunction(MachineFunction &MF) {
  46   const XCoreInstrInfo &TII =
  47       *static_cast<const XCoreInstrInfo *>(MF.getSubtarget().getInstrInfo());
  48   unsigned StackSize = MF.getFrameInfo().getStackSize();
  49   for (MachineBasicBlock &MBB : MF) {
  50     for (MachineBasicBlock::iterator MBBI = MBB.begin(), EE = MBB.end();
  51          MBBI != EE; ++MBBI) {
  52       if (MBBI->getOpcode() == XCore::FRAME_TO_ARGS_OFFSET) {
  53         MachineInstr &OldInst = *MBBI;
  54         Register Reg = OldInst.getOperand(0).getReg();
  55         MBBI = TII.loadImmediate(MBB, MBBI, Reg, StackSize);
  56         OldInst.eraseFromParent();
  57       }
  58     }
  59   }
  60   return true;
  61 }