XCoreFrameLowering.cpp | Explore in Territory

//===-- XCoreFrameLowering.cpp - Frame info for XCore Target --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains XCore frame information that doesn't fit anywhere else
// cleanly...
//
//===----------------------------------------------------------------------===//

#include "XCoreFrameLowering.h"
#include "XCore.h"
#include "XCoreInstrInfo.h"
#include "XCoreMachineFunctionInfo.h"
#include "XCoreSubtarget.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetOptions.h"
#include <algorithm>

usingnamespacellvm;

static const unsigned FramePtr = …;
static const int MaxImmU16 = …;

// helper functions. FIXME: Eliminate.
static inline bool isImmU6(unsigned val) { … }

static inline bool isImmU16(unsigned val) { … }

// Helper structure with compare function for handling stack slots.
namespace {
struct StackSlotInfo { … };
}  // end anonymous namespace

static bool CompareSSIOffset(const StackSlotInfo& a, const StackSlotInfo& b) { … }

static void EmitDefCfaRegister(MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator MBBI,
                               const DebugLoc &dl, const TargetInstrInfo &TII,
                               MachineFunction &MF, unsigned DRegNum) { … }

static void EmitDefCfaOffset(MachineBasicBlock &MBB,
                             MachineBasicBlock::iterator MBBI,
                             const DebugLoc &dl, const TargetInstrInfo &TII,
                             int Offset) { … }

static void EmitCfiOffset(MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator MBBI, const DebugLoc &dl,
                          const TargetInstrInfo &TII, unsigned DRegNum,
                          int Offset) { … }

/// The SP register is moved in steps of 'MaxImmU16' towards the bottom of the
/// frame. During these steps, it may be necessary to spill registers.
/// IfNeededExtSP emits the necessary EXTSP instructions to move the SP only
/// as far as to make 'OffsetFromBottom' reachable using an STWSP_lru6.
/// \param OffsetFromTop the spill offset from the top of the frame.
/// \param [in,out] Adjusted the current SP offset from the top of the frame.
static void IfNeededExtSP(MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator MBBI, const DebugLoc &dl,
                          const TargetInstrInfo &TII, int OffsetFromTop,
                          int &Adjusted, int FrameSize, bool emitFrameMoves) { … }

/// The SP register is moved in steps of 'MaxImmU16' towards the top of the
/// frame. During these steps, it may be necessary to re-load registers.
/// IfNeededLDAWSP emits the necessary LDAWSP instructions to move the SP only
/// as far as to make 'OffsetFromTop' reachable using an LDAWSP_lru6.
/// \param OffsetFromTop the spill offset from the top of the frame.
/// \param [in,out] RemainingAdj the current SP offset from the top of the
/// frame.
static void IfNeededLDAWSP(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator MBBI, const DebugLoc &dl,
                           const TargetInstrInfo &TII, int OffsetFromTop,
                           int &RemainingAdj) { … }

/// Creates an ordered list of registers that are spilled
/// during the emitPrologue/emitEpilogue.
/// Registers are ordered according to their frame offset.
/// As offsets are negative, the largest offsets will be first.
static void GetSpillList(SmallVectorImpl<StackSlotInfo> &SpillList,
                         MachineFrameInfo &MFI, XCoreFunctionInfo *XFI,
                         bool fetchLR, bool fetchFP) { … }

/// Creates an ordered list of EH info register 'spills'.
/// These slots are only used by the unwinder and calls to llvm.eh.return().
/// Registers are ordered according to their frame offset.
/// As offsets are negative, the largest offsets will be first.
static void GetEHSpillList(SmallVectorImpl<StackSlotInfo> &SpillList,
                           MachineFrameInfo &MFI, XCoreFunctionInfo *XFI,
                           const Constant *PersonalityFn,
                           const TargetLowering *TL) { … }

static MachineMemOperand *getFrameIndexMMO(MachineBasicBlock &MBB,
                                           int FrameIndex,
                                           MachineMemOperand::Flags flags) { … }


/// Restore clobbered registers with their spill slot value.
/// The SP will be adjusted at the same time, thus the SpillList must be ordered
/// with the largest (negative) offsets first.
static void RestoreSpillList(MachineBasicBlock &MBB,
                             MachineBasicBlock::iterator MBBI,
                             const DebugLoc &dl, const TargetInstrInfo &TII,
                             int &RemainingAdj,
                             SmallVectorImpl<StackSlotInfo> &SpillList) { … }

//===----------------------------------------------------------------------===//
// XCoreFrameLowering:
//===----------------------------------------------------------------------===//

XCoreFrameLowering::XCoreFrameLowering(const XCoreSubtarget &sti)
    : … { … }

bool XCoreFrameLowering::hasFP(const MachineFunction &MF) const { … }

void XCoreFrameLowering::emitPrologue(MachineFunction &MF,
                                      MachineBasicBlock &MBB) const { … }

void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const { … }

bool XCoreFrameLowering::spillCalleeSavedRegisters(
    MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
    ArrayRef<CalleeSavedInfo> CSI, const TargetRegisterInfo *TRI) const { … }

bool XCoreFrameLowering::restoreCalleeSavedRegisters(
    MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
    MutableArrayRef<CalleeSavedInfo> CSI, const TargetRegisterInfo *TRI) const { … }

// This function eliminates ADJCALLSTACKDOWN,
// ADJCALLSTACKUP pseudo instructions
MachineBasicBlock::iterator XCoreFrameLowering::eliminateCallFramePseudoInstr(
    MachineFunction &MF, MachineBasicBlock &MBB,
    MachineBasicBlock::iterator I) const { … }

void XCoreFrameLowering::determineCalleeSaves(MachineFunction &MF,
                                              BitVector &SavedRegs,
                                              RegScavenger *RS) const { … }

void XCoreFrameLowering::
processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                    RegScavenger *RS) const { … }
llvm/llvm/lib/Target/XCore/XCoreFrameLowering.cpp
