1 files changed, 180 insertions, 0 deletions

diff --git a/contrib/llvm-project/llvm/lib/Target/Mips/Mips16FrameLowering.cpp b/contrib/llvm-project/llvm/lib/Target/Mips/Mips16FrameLowering.cpp
new file mode 100644
index 000000000000..5a2a916a6b7a
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Target/Mips/Mips16FrameLowering.cpp
@@ -0,0 +1,180 @@
+//===- Mips16FrameLowering.cpp - Mips16 Frame Information -----------------===//
+//
+// 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 the Mips16 implementation of TargetFrameLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Mips16FrameLowering.h"
+#include "MCTargetDesc/MipsBaseInfo.h"
+#include "Mips16InstrInfo.h"
+#include "MipsInstrInfo.h"
+#include "MipsRegisterInfo.h"
+#include "MipsSubtarget.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/IR/DebugLoc.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MachineLocation.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/CodeGen/TargetFrameLowering.h"
+#include <cassert>
+#include <cstdint>
+#include <vector>
+
+using namespace llvm;
+
+Mips16FrameLowering::Mips16FrameLowering(const MipsSubtarget &STI)
+    : MipsFrameLowering(STI, STI.getStackAlignment()) {}
+
+void Mips16FrameLowering::emitPrologue(MachineFunction &MF,
+                                       MachineBasicBlock &MBB) const {
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+  const Mips16InstrInfo &TII =
+      *static_cast<const Mips16InstrInfo *>(STI.getInstrInfo());
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+
+  // Debug location must be unknown since the first debug location is used
+  // to determine the end of the prologue.
+  DebugLoc dl;
+
+  uint64_t StackSize = MFI.getStackSize();
+
+  // No need to allocate space on the stack.
+  if (StackSize == 0 && !MFI.adjustsStack()) return;
+
+  MachineModuleInfo &MMI = MF.getMMI();
+  const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
+
+  // Adjust stack.
+  TII.makeFrame(Mips::SP, StackSize, MBB, MBBI);
+
+  // emit ".cfi_def_cfa_offset StackSize"
+  unsigned CFIIndex = MF.addFrameInst(
+      MCCFIInstruction::createDefCfaOffset(nullptr, -StackSize));
+  BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
+      .addCFIIndex(CFIIndex);
+
+  const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
+
+  if (!CSI.empty()) {
+    const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
+
+    for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
+         E = CSI.end(); I != E; ++I) {
+      int64_t Offset = MFI.getObjectOffset(I->getFrameIdx());
+      unsigned Reg = I->getReg();
+      unsigned DReg = MRI->getDwarfRegNum(Reg, true);
+      unsigned CFIIndex = MF.addFrameInst(
+          MCCFIInstruction::createOffset(nullptr, DReg, Offset));
+      BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
+          .addCFIIndex(CFIIndex);
+    }
+  }
+  if (hasFP(MF))
+    BuildMI(MBB, MBBI, dl, TII.get(Mips::MoveR3216), Mips::S0)
+      .addReg(Mips::SP).setMIFlag(MachineInstr::FrameSetup);
+}
+
+void Mips16FrameLowering::emitEpilogue(MachineFunction &MF,
+                                 MachineBasicBlock &MBB) const {
+  MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+  const Mips16InstrInfo &TII =
+      *static_cast<const Mips16InstrInfo *>(STI.getInstrInfo());
+  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+  uint64_t StackSize = MFI.getStackSize();
+
+  if (!StackSize)
+    return;
+
+  if (hasFP(MF))
+    BuildMI(MBB, MBBI, dl, TII.get(Mips::Move32R16), Mips::SP)
+      .addReg(Mips::S0);
+
+  // Adjust stack.
+  // assumes stacksize multiple of 8
+  TII.restoreFrame(Mips::SP, StackSize, MBB, MBBI);
+}
+
+bool Mips16FrameLowering::
+spillCalleeSavedRegisters(MachineBasicBlock &MBB,
+                          MachineBasicBlock::iterator MI,
+                          const std::vector<CalleeSavedInfo> &CSI,
+                          const TargetRegisterInfo *TRI) const {
+  MachineFunction *MF = MBB.getParent();
+
+  //
+  // Registers RA, S0,S1 are the callee saved registers and they
+  // will be saved with the "save" instruction
+  // during emitPrologue
+  //
+  for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+    // Add the callee-saved register as live-in. Do not add if the register is
+    // RA and return address is taken, because it has already been added in
+    // method MipsTargetLowering::lowerRETURNADDR.
+    // It's killed at the spill, unless the register is RA and return address
+    // is taken.
+    unsigned Reg = CSI[i].getReg();
+    bool IsRAAndRetAddrIsTaken = (Reg == Mips::RA)
+      && MF->getFrameInfo().isReturnAddressTaken();
+    if (!IsRAAndRetAddrIsTaken)
+      MBB.addLiveIn(Reg);
+  }
+
+  return true;
+}
+
+bool Mips16FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
+                                          MachineBasicBlock::iterator MI,
+                                       std::vector<CalleeSavedInfo> &CSI,
+                                       const TargetRegisterInfo *TRI) const {
+  //
+  // Registers RA,S0,S1 are the callee saved registers and they will be restored
+  // with the restore instruction during emitEpilogue.
+  // We need to override this virtual function, otherwise llvm will try and
+  // restore the registers on it's on from the stack.
+  //
+
+  return true;
+}
+
+bool
+Mips16FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  // Reserve call frame if the size of the maximum call frame fits into 15-bit
+  // immediate field and there are no variable sized objects on the stack.
+  return isInt<15>(MFI.getMaxCallFrameSize()) && !MFI.hasVarSizedObjects();
+}
+
+void Mips16FrameLowering::determineCalleeSaves(MachineFunction &MF,
+                                               BitVector &SavedRegs,
+                                               RegScavenger *RS) const {
+  TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+  const Mips16InstrInfo &TII =
+      *static_cast<const Mips16InstrInfo *>(STI.getInstrInfo());
+  const MipsRegisterInfo &RI = TII.getRegisterInfo();
+  const BitVector Reserved = RI.getReservedRegs(MF);
+  bool SaveS2 = Reserved[Mips::S2];
+  if (SaveS2)
+    SavedRegs.set(Mips::S2);
+  if (hasFP(MF))
+    SavedRegs.set(Mips::S0);
+}
+
+const MipsFrameLowering *
+llvm::createMips16FrameLowering(const MipsSubtarget &ST) {
+  return new Mips16FrameLowering(ST);
+}